This is because you are looking at it from a different POV.
It's really annoying to have to answer to the same question for the 10th time.
It's really annoying to try to explain to someone who doesn't even know what "upload the X file to the Y directory" means.
It's really annoying to be bugged by IM or PMs for support.
It's really annoying to read people reporting bugs that don't exist because they didn't read the instructions.
It's really annoying to read feature requests that are already in the product
It's really annoying to hear things like "how do I make a link in HTML?" by a forum admin! Gosh, someone is supposed to know some things before starting his own forum!!
And the list goes on and on and on...
Wouldn't YOU get mad???
(In fact I am mostly calm in such situations but some times I really wanted to swear to the person

)