Wow, I'm /really/ liking this idea. And it's not something I'd've thought of, so my mind is pretty much blown by how simple and yet awesome it would be. :)
Forum God brought up a good point though, because I too use "haha" a lot. It's kind of awkward when I'm in a party, but talking to another buddy in buddy chat or by whispering, because I'll constantly F2 and my party will wonder what the heck I'm so happy about. xD Maybe they should change it so that the triggers only work if they're in /all chat, or make that an option.