Okay, as I outlined already in my comments, I am also doing this on other SE sites: i.e. not accepting too quickly. It may lead to forgetting to accept an existing answer temporarily, but inside your profile a nagging notice will appear over questions you have asked but on which you didn't accept any answer:
Have you considered accepting an answer or starting a bounty for this question?
My main reason is indeed that I know from the other side of the fence how discouraging it is to find that a question that was the first, already got the most upvotes or was written by the guy with the most reputation in the room and therefore gets accepted "by default".
As Camil Staps points out:
When an answer is already accepted, this discourages others to answer as well, as the question seems 'done'.
It's too true, because doing it creates a dynamic of its own and doesn't necessarily foster the quality of the answers but instead quantity or speed. Often questions will be short and still to the point, but more often it seems to give an advantage to have high rep already. The quality of these answers is in many cases no better than what exists as answer from a lower rep user, but for some reasons the high rep user will garner the upvotes anyway "by default".
There are so many answers out there on all of the SE sites and oftentimes I go *facepalm* and sit down to write up a comprehensive answer to a rather old question well knowing that I won't get (m)any upvotes for it. The whole Q&A spirit of the SE sites demands I do it. After all these sites have a high search engine rank and people will come here to look for answers and often consider them authoritative. Hence it is very important to foster the quality and not the speed or quantity of answers.
An existing answer that tells you that you can't do something even though you can full well do it, but was accepted because either the OP gave into the nagging notice (Have you considered accepting an answer ...) in his/her profile or didn't know better, doesn't really encourage to write up another better and more comprehensive answer when you know that all you do is "wasting time" (because the topic is a niche topic in the first place) and you won't get gratification by means of upvotes either.
So to reiterate: this is a discussion and I fully support Camil Staps' view because I'd like quality to be a more relevant metric than quantity.