People are maybe reading too much into Marigold's character and as an introvert myself, I'd put 99% of her faux pas down to her having limited skills in social interaction and behaviour.
When I was growing up as a teen, I'd get home from school, go up to my room, boot up my computer and only leave my room for toilet breaks and to get food. I've almost certainly suffered from computer addiction but was maybe fortunate that at the time 9.8 baud modems ruled the internet. Certainly there was nothing like WoW to get seriously addicted to. Knowing I lacked social skills, I made a point of going to nightclubs with people from school/college in order to learn some social skills but it was a waste of time. If you are introverted and aren't naturally outgoing, social scenes can be uncomfortable. Going to the nightclubs were a waste for me as I never had the skills to chat up the ladies and even if one did catch my eye, the lack of knowing the protocol as to whether or not it would be a one night stand or something more would be expected would be a major concern. I never got on the dance floor due to a lack of knowledge of how to dance (even if it was clear other individuals couldn't either). When I am at work functions, I'll lurk in the corners and only speak to individual people who are not part of a group and that I have regularly interacted with before. I can be talkative one on one, but put me in a group and I shut up. The irony that while in a group, in an attempt to be careful with what you are saying so not to insult anyone, you are more likely to insult people - so sometimes the best thing to do is to say little unless you know the people well. I'd wager the same is with Marigold who appears to be more introverted than what I am. (I tend to score around 1.8 on the introvert-extrovert scale where 1 is introvert and 5 is extrovert)
In terms of 'real' friends, Marigold only has Angus, Momo, and her WoW guild (as a single entity rather than any individuals within). It is clear Hanners is likely to get full friend status very soon. Observe that of her friends, only Angus is a full human - Momo is a computer and her WoW guild interacts via a computer. I predict that Dale will become her first real boyfriend in the long term future in a Romeo and Juliet type situation (minus the poison and deaths etc) thanks to the server rivalry. People like Faye and Martin to introverts like Marigold will probably be classified as "friends of Angus" rather than friends in their own right, no matter how often they interact. As a result, I wouldn't expect Marigold to interact with "friends of Angus" unless Angus (or Hanners) is there or that the likes of Faye approach her and 'drag' her along. Expect Marigold to put herself out to help Angus and Hanners, but not for Martin etc unless she feels something to gain - this is not a negative reaction it appears since the more social of us would help strangers out in need but not go that extra mile for them. Same with Marigold who won't see Martin etc as a full friend. For someone like Marigold, Angus (and increasingly so Hanners) will be her security blanket in a group. Although she is spending increasing amount of time with the main cast of QC, she won't be comfortable enough or know them well enough for equal interaction (not unless alcohol is involved and from memory she only drinks to make the effort of fitting in). By equal interaction, I mean that 99% of her conversations with the likes of Martin will be started by the group and she will look to answer politely. In relation to her friends (Angus, Momo, her guild and when alone with Hanners), she will probably start closer to half the conversations.
I don't think Marigold is any more self centered than anyone else in the world. I think where people have commented about her behaviour from the time she came back from time with the main QC cast while Momo was going her raids for her is missing the point. From an introverts' position, spending time with a group of people without knowingly offending or making an idiot of yourself is a HUGE deal. Remember the start of that evening was:
http://www.questionablecontent.net/view.php?comic=1463. You'd forgive a man who has become a father for the first time coming back from the hospital and being caught up with himself being a father for the first time - for Marigold it is probably on a similar scale, but unless you are introverted yourself, you will think Marigold is being caught up in something that most would consider is no big deal.
http://questionablecontent.net./view.php?comic=1628Consider the time while sitting on the couch when Marigold told Faye she really liked Angus - leading to Faye making a quick exit when Angus came in - and then the joyous face when Faye left. Her joy in real life would not be purely down to the fact Faye seemingly took the hint to leave them alone - she probably took a bit of joy from the fact Faye didn't blow her off and tell her that Angus wouldn't be interested in her etc. Even if she saw the eyes pf Faye and Angus at the time, she wouldn't have necessarily known what the look meant. Or at least - she might have realised something was up, but she wouldn't have had the experience to know why.
Or take the time when everyone is out in the bar etc and then the last frame of the comic is Marigold sitting at her computer looking bored and sighing. It is probably wrong to say she is self-pitying. I'd argue her emotion is one of disappointment in herself and not one of pity. There is a difference and I doubt she'd want to be pitied. A sportsman who comes runner up will show signs of disappointment but won't be expecting pity - I hope the comparision explains what I mean.
I don't know how introverted Jeph is, or if he knows people like Marigold, but I think he has got the behaviour of an introvert to the level of Marigold more or less spot on to date. I've rarely set out to insult people or act rude, but awkwardness in situations can lead to situations that socially aware people can spot and navigate around. Any perceived rudeness from Marigold is almost certainly 99% unintentional. Compare that with the likes of Dora or Faye who built their reputations on 'sassing' people out.
(for the side issue of her magazines, again I think people are slightly missing the point. If I lend someone one of my books, then it doesn't matter if the spine is bent and there is a coffee cup mark on the cover where I once used the book as a cup coaster - the point is the person who is borrowing the book has a duty of care to return the book back in the condition they were lent it and not add to the stains etc. Whether or not the magazines are expensive or not is beside the point.)
So why does Angus think Marigold is great? In the context of their long term relationship, rather than how we have seen her react in group context, she is. As stated above, introverts normally have 1-2 good friends and so tend to have level of loyalty that extroverts don't have. Due to the relative ease that extroverts have in making new friends, extroverts tend to have more of an "easy come, easy go" attitude towards their friends. If a friend starts to become annoying, extroverts are more likely to discard them and find a different friend to hang around with. Introverts like Marigold don't have that option. Although we won't witness it (and it would be boring to read from a comic angle), Marigold will provide loyal, solid, committed friendship towards Angus. Marigold will always take Angus's side in any argument (their few minor spats aside), she will always be a loyal confidante who he can always confide in (more so than Faye or any other girlfriend or friend) and is the one person who isn't likely to betray him. She certainly won't critisise him unless he gives indication he wants her opinion, but I suspect he will appreciate it if he went too far that she does feel the need to react without asking. Due to her introverted nature, Angus won't need to deal with the baggage that extroverts sometimes have - certainly not needing to put up with her in terms of relationship dramas or emotional outbursts. All in all, they seem to rarely argue and are comfortable around each other - almost like a brother and sister but without the siblin rivalry.
Considering further Marigold's role in QC, she will always be introverted - no professional help will change that. She may develop stronger friendship bonds but will only have 2-3 real life friends at any point in time (ie, Angus, Hanners and maybe one other - it is hard to classify Momo due to her non-human status). It won't be in her nature to want to build a bigger group of friends than that, although for as long as Angus and Hanners are part of the QC crowd, she will be considered part of the friendship group. However, in her own mind she will not consider herself a fully paid up member of the group and will therefore opt in and out of group activities on a "as needs" basis. The longer she spends hanging out with the group, the more she'll learn the social protocols and will learn when she should keep quiet and when to speak although she will still at times feel awkward. For example, most of us know the protocols in terms of having a conversation on the phone, but not everyone is comfortable actually picking up the phone and making the call. We all know how to pee in public toilets but some people have problems if there is someone is using the toilet next to theirs....... Myself, if I make a phone call and get voice mail, I have to put the phone down, scribble a note of what I want to say and then redile - even if the message is "its me, call me back on number blah blah blah". Completely irrational but I've never been comfortable with speaking to technology down the other end of the phone but I'm ok speaking to a human live.
Marigold will never be one of the main characters, even if she is still involved several real life years down the line. As per the likes of Sven, Steve, Tai and a few others, she is one of the main background characters who will be come and go and help move things along now and again in whatever storyline is happening. Her introvertedness means she can disappear for periods without it seeming suspicious. Her absence is explained with "probably on a raid". At the moment, her main function is to help Hanners overcome some of her OCD. Both are socially inexperienced in some areas (such as boyfriends etc) although for different reasons.
For me, the most natural storyline that is focused on Marigold is a relationship with Dale who seems to have his eye on her and sees her as an online project. They are forbidden fruit for each other thanks to their class and server etc on WoW in the same way Romeo and Juliet were forbidden due to their family names and feuds. I suspect Marigold will be socially confused by the fact she'll probably be flattered by Dale's attention once his attention becomes obvious but sees him as the enemy. Of course, we won't see the fruitation of Dale's scheme for a while, but it would be interesting if Marigold does get a romance interest at a time when Angus and Faye has a major fight - as per above, by the nature of Marigold's personality, she will always be there for Angus but will her mind and attention be partly on other things?? Marigold bonding with Dale isn't so unlikely considering both have spend considerable time on WoW and their first date will probably be in a WoW tavern.
So in conclusion, I think Marigold is a good honest person without any deliberately negative attributes. However when in a group situation or away from her closest friends of whom she is most familiar with, she acts in a way she *thinks* people are supposed to - but without social experience she sometimes gets it wrong and may unintentionally offend. For most people, being introverted or extroverted is not a huge problem, but when your 'vertedness is a little bit more extreme then the behaviour patterns become strange or out of sync with normal practices. Hanners also have wierd habits but we let her off once we are informed she has the excuse of OCD.
(Thank you for reading)