I have a terrible memory so forgive me If I've brought this up already, but one thing that took me a very hard time to realize last season when Elena drove me batty, was that she's only 17. as a teenager your emotions are all over the place to begin with, and add to that an emotionally exhausting year, and you're going to snap. Bonnie's in the same boat right now-she's not stefan, who has had 145 years of keeping his emotions in check. That's why I can more easily forgive Bonnie than Damon. Damon should know better, Bonnie not so much.