What are Accepted Answers and how are they different on User Experience?
Should I accept answers to my questions?
Should I refrain from answering a question with an accepted answer?
Accepting an answer basically marks it as "This works for me!" and gives the accepted answer a green check mark to note it as accepted, and also gives a 15 rep bonus to the answerer.
Unlike many sites, on User Experience there's often no one acceptable answer however. Some users almost never accept answers to avoid giving the impression that only one answer is acceptable, and many of us wait a fair amount of time before accepting to see what other answers come in.
Yes, accepting shows either you consider a solution to be "the best" or you have decided to go with a particular solution provided in an answer.
However, since there's often no one right answer, you should wait at least a day or two to accept an answer to see what other answers pour in; don't just accept the first answer. Accepting an answer gives the unfortunate impression that a question is "finished". Give the answers and answerers the respect they deserve by giving everyone time to answer and give the community time to evaluate and point out strengths/weaknesses in the answers to your question.
The first answer to your question might work, but if you wait until a couple more answers are added you can pick the solution that works best. If there really is not a best solution, not accepting an answer is also okay; you don't have to accept an answer for every question you ask.
Certainly not! As mentioned above, accepted answers mean a little less on User Experience. That doesn't mean an Accepted Answer is meaningless, but if you have an answer that's different from all that is posted that you think is valuable enough to post, by all means do.
Community voting will help show the worth of your answer and users of this site tend to read past the accepted answer to see all solutions. Don't be discouraged by the accepted answer, as long as you have something valuable to add, add it.