In general, answers are being accepted by the original posters way too fast. When only one short answer has been provided and the answer accepted only hours after it was posted (with no other time for other people to post), then something is broken with the users. More examples: 1, 2, 3, 4, 5, and 6.
Yes, I know that the OP can always change their vote, but an overly fast acceptance rate will discourage people from submitting thorough answers, or even from submitting questions at all.
The difference in motivation provided by seeing one short answer with only one or two upvotes and seeing the same answer that also been accepted by the OP is tremendous.
I would like us to encourage OPs to wait longer to let the community put several answers together for each question before selecting preferred answers. If we don't, the site will get populated by questions and answers the community hasn't put the time into polishing and people's first impressions will be that it's insufficiently introspective to warrant visiting.