So there is a "best answer" but why not the opposite?

For now it's enough that we have ratings, we can "reward" such answers with "-" ratings. It would be a hard task to choose "worst answer" from so many responses...

Yes, I think I agree with you. The number of people I've seen come in with "I don't know" as a response to every discussion is sickening. I try to answer as full as I can, and for my trouble, I have just had 5 points deducted by Mylot. What for?

Considering the multitude of crap responses that most posts get, I think it would be impossible to choose a worst answer. ;) Yeah, that was tongue in cheek. Probably because a lot of mylot is earning rewards, and there's no reward for a worst answer. Whereas if your answer is chosen as best answer, you get extra earnings.