Ok, here's what I don't get. The metric system, for the most part, makes sense. The only thing that seems unnecessarily complicated is the definition of a meter as "the length of the path travelled by light in vacuum during a time interval of 1/299,792,458 of a second." Ok, if that's how you're going to measure a meter, and you already know how generally long it is, why not define a meter as an even 1/300,000,000th of a light second?