I find it rather hilarious when people yap on about how one online game has a worse community than another.
Having played many online games I can only say: that isn't true.
There isn't that much difference between communities at all. 90% of all random runs are just silent people doing stuff. Might as well be bots.
However, I agree with Bovinity in one aspect: peoples patience and by direct correlation "niceness" is highly dependent on how much any given game makes them farm content. The more they have to farm, the more impatient and less tolerant they are of mistakes, because the "just want to get shit done" mentality kicks in.