I find that kind of amusing since, when he was first introduced, Stuart came across as pretty confident and emotionally well-adjusted. It wasn't until later on that he became the sad and depressing caricature he is now.
Yeah, in one of the earlier episodes he's pretty smooth when he hit on Penny by way of drawing her and getting her interest. He's still a nerd but he didn't freeze up automatically when meeting a pretty girl and had some witty lines.. kind of some of the nerds i know when they're on a good day.
Unfortunately he's now the show's sadsack used for cheap laughs and the very worst clichee of nerds (never mind that he's got his own business doing something he loves). He's become the punching bag of the show and BBT should be better than that. I seem to recall he should've been promoted to series regular during the Wollowitz in Space storyline but i guess they decided against it, maybe they thought the cast is big enough as it is.