Nothing wrong with glitter, provided one isn't Hanners… and you're not putting it on your face.
One of the hardest forms of addiction to break is addiction to an emotional state. When you're addicted to stress and anger and depression, it doesn't matter what is happening in your life, you will find something to stress out and become angry about (which will then turn into depression).
Stress and anger give us a short boost of adrenaline, which gives us a temporary high, and make us feel like we're in control of situations that we're totally not--after all, we're caring about the situation, and that's like doing something, isn't it? And then depression kicks in once we realize just how powerless (or, if not powerless, ineffectual) we are--and, as a nice little button, often helps us embrace victimhood as an excuse for not making the changes in our lives that would end the cycle.
Eventually, we get habituated to existing in a particular mental state, and WILL find whatever way is available to keep us in that mental state. My theory is that half the people in the world (probably more) who follow either sports or politics only do so because they want an excuse to be outraged at any given time.
And here's where it comes back 'round to the comic: Marten lives in a headspace of uncertainty and a vague sense of mild depression. That's home to him; it's where he's comfortable, because he understands it. He doesn't enjoy it (who would?), but, speaking as someone wallowing in a crappy job, apartment, and city, I gotta tell you, it's hard to leave the devil you know for the angel you don't.
Marten isn't Al Bundy--he doesn't have to stay in a particular headspace because the series would be over without it, so I don't think that this is just a way of maintaining the status quo. Really, Jeph has never been a creator who embraces the status quo style of comic-writing; I think this is Jeph really playing out the character logically: Marten grabs things that he think will make him happy, but, because he isn't changing the way he approaches life, he ends up spoiling it for himself by hunting down whatever will ruin the experience for him. The fact that he recognizes that is a good thing, though... if he does something about it.
So, really, this was probably just a thing that happened on the way to other things and its immediacy is the only thing giving it real importance (although it is a nice little ticking time-bomb in his friendship with Elliot).
Two things: one, while I agree there is such a thing as addiction to emotional states, that's not quite what you're describing when you get to what you call Marten's 'headspace.' I've remarked on this before: people have a tendency to adhere to what's familiar, be it working well for them or not. Many a person will endure fairly horrible, stressful conditions rather than venture into a new situation, because the terrors of dealing with the new are, to him, worse. Change holds great fear for many people, and they will go to great lengths to avoid it. I wouldn't call it an addiction to that familiar state, though; it's fear, plain and simple. In other words, avoidance, rather than need (and yeah, the two can get intermixed, but that's a whole other ball of wax).
Dora, as I've said before, is a good example of a person who fears the unfamiliar; she'd rather move from failed relationship to failed relationship than try to change things about herself in order to make a relationship last: being in a relationship that won't last is what's familiar to her. When things didn't end with Marten the way she'd expected they would, Dora got afraid, and when that didn't work, she got angry, with the result being she finally had an excuse to end the relationship, which is the outcome she'd been expecting all along.
Marten, to me, doesn't seem in quite this place. He's not so much stuck in a pattern as he is directionless. I suppose that, too, could be considered a pattern, but we've yet to see Marten actively struggle not to have a direction, so to me, anyway, the jury's still out on that. On the other hand, were Marten 'addicted' to moping, or were that his familiar place, it seems far more likely to me he'd have turned down Dora and kept waiting for Faye, using one excuse after another to not move on. One could argue he picked Dora because he knew it couldn't last, but it doesn't seem to me he knew her well enough at the time to predict that.
So I think Marten is basically still in the 'down' after what happened with Dora, and, as I said, the 'fresh' little down of realizing Padma will soon be leaving pushed him back downslope a little. And yet, rather than wallowing in that, we see him trying to work his way back 'up' by examining the situation and explaining to himself that a little fun with Padma is a good thing.
Meanwhile, I love seeing Pot Faye sitting next to him, piping away about how 'black' Kettle Marten is (when he's mildly smudged at best). Until recently, Faye's a poster child for staying in one place, and she's fresh off another attack of it.