Many [...] design decisions have their roots in my dislike for forcing people to do things in some particular way [...] Often, I was tempted to outlaw a feature I personally disliked, I refrained from doing so because I did not think I had the right to force my views on others.
Bjarne Stroustrup. Source: The Desing and Evolution of C++ (1.3 General Background)
I'm not trying to be nice. I'm trying to be helpful.
Edit: Due to introduction of "Nice Regime" to SO (http://meta.stackexchange.com/help/be-nice), I've stopped answering questions. If I want to have fun, I watch a movie. If I want to be nice, I chat with my friend. If I want an answer, I use SO. It was as simple as that. I strongly support the don't be rude notion, I strongly oppose the you have to be nice notion. Information ain't nice or rude by itself, it's the people who are. By forcing the people to express feelings, we're essentially removing the value of the emotions conveyed, and we're polluting the information plane.
Also - I'm usually downvoting every single person not answering the question asked or answering it in a way that makes OP unaware of the solution's caveats. If somebody asks for "a solution without XY", an answer telling him "use XY" or "don't do it at all" is not an answer. It's a valid comment, yes - not an answer though. Telling him "it's a stupid question" - regardless of the exact way it's spelled out - without providing any attempt to answer the question is not a valid answer also. You don't have to be overly polite - but try to be factual and spot-on.