I guess there are three responses I'll give when someone posts a question that has already been answered a dozen times and can be found with a little effort on the part of the poster (OP):

1. Post the answer yet again
2. Post a comment instructing the OP to search for their answer
3. Post nothing as it's just a pain in the arse repeating what is already available

I believe that once a question has been answered more than half a dozen times in separate threads it becomes a little unnecessary to keep answering it again and again, leaving me with options 2 & 3.

Option 3 is far less helpful than option 2, so often I will take the option 2 route but I think I should at least provide the keywords the OP needs to search with (I must admit I haven't always done this, but will try to in future). Telling someone to use search is an entirely valid answer, provided they are told what to search for (which may not always be obvious to the OP).

There's no reason for it to get nasty though or for anyone to resort to harassment, but unfortunately some OP's don't like being made to look stupid/lazy in public, and some posters are possibly a little too aggressive at times when telling the OP to go search (too much coffee, not enough sex, tripped over the dog, whatever).

What GeneralAntilles says is correct though, there are people here who spend a lot of time answering queries and it's often annoying to see someone post the same often answered questions without making any effort to see if it's already been answered before - that's pretty lame behaviour and ignorance isn't always an excuse.