Oh yeah, the ^_^ face looks bad in some of the wider fonts.

I sometimes feel that pull to adopt something as a convention because it seems reasonable to me. But then I realize that it's not really a convention if no one understands or follows it, and it requires a lot of work to explain and popularize. So I'm always left reminding my own brain of its pointlessness despite its ... seeming reasonableness. For (a California-specific) example, I always want to signal left in a left-turn lane to let the people behind me to know that I'm going to U-turn. But I'm probably the only person that does that so people behind me just figure I didn't turn my signal off or whatever. =/

I think people who regularly talk to you probably pick up on your smiley meanings intuitively; people hopefully don't regularly drive behind me.