People who assume everyone knows how to use a forum. When I 1st came here I didn't know a lot of things. Didn't know what it meant when I changed to Skilled...figured "who thinks that?". And jumping on a person with one post, especially when they posted with something that makes them mad. Assuming everyone knows what we know. Forgetting there is a real person at the other end who may really be stressing over a PC problem that they know little about. And yes, manners...acting online in a manner that they never would in person (I hope!).
A friendly hello, and an offer of assistance, as was offered, is the right way. People who assume (ass u me).
Intolerance, bigotry, haughtiness, snideness, uncaring...as was mentioned, a smile costs nothing, and manners are always called for. A Guy