On Stack Overflow, where I usually spend my time, the questions are mostly objective, and failing to accept a correct answer is generally sloppy.
Here, the topics can be much more subjective. Case in point: Word that means "more accepting of other cultures"? has a lot of good answers, none are really "correct". In that case, the votes and comments are a good indication of how helpful/valid an answer is. I accepted an answer because SO etiquette demands closure, but is it bad form to not accept any answers here?