It's unfortunate that your question was downvoted, but sometimes that's life. I would've rather you looked around and participated for more than a week and asked more than two questions (one of which, by your own admission, was "stupid") before forming an opinion of the site. However, since you brought it up here, let me try to address a few points.
I disagree with your hypothesis that people here are impatient with new comers. I've been here for a while and I can recollect several examples where experienced users were extremely patient with newcomers. While we certainly don't greet every single question with welcome comments, we do try our best to help the OP.
I'm reading your question for the first time today and the first thing that struck me was
I don't know the effect of
It sounds like you were indifferent and lazy (I'm not implying that you were). What
MeshFunction does is just a single key press away — just press F1! It's a different issue if you tried reading it and had trouble with a specific part of it, but that wasn't the case here. And sure enough, the first comment was also pointing out the same. The next line that stood out was:
How to get the desired obvious result?
but you hadn't explained or mentioned what you desired or what was "obvious". I have an idea of what is obvious to me, but it is not obvious if that is also what's obvious to you... Since Szabolcs pointed out two instances of confusion/lack of clarity in the question, you could have tried to rephrase it or include what you tried after reading the docs for
I cite these examples, not to dissect your question, but to point out that sometimes (especially in text), it's very hard to convey tone and indicate your sincerity/effort properly. Your phrasing of the question at certain places and the lack of detail had the unfortunate effect of sounding like you just grabbed some code from somewhere and wanted us to make it run like what you imagined. Someone else reading the question might have come to the same conclusion and downvoted for lack of effort.
Also note that we get several questions every day from new users that are just off-loading their homework on to us or want something "done right now", but don't know the language and don't want to learn. A good tip to get the members to treat your question better than those of the drive-by users, is to try and differentiate your question from theirs :)