Little have I witnessed an individual necro-thread an old thread or get off-topic just to be like, "Trololo, herp derp." However that doesn't mean I have witnessed it happen before. It does generally annoy me, but not as much if I see the member do it only once. I keep in mind that the Feralheart forums are one of the most active forums I've seen in an extremely long time. Therefore, a bit of confusion can happen to those who are new forum-wise. I have to admit, it took me a bit of observing here and there to understand how things ran before I began to dedicate myself.
The point is, if an individual gets off-topic or necro-threads once, then I can be a bit more tolerable. However when I see an individual do it over and over, that's when I get agitated. What I don't get is why some individuals feel the need to post in a thread that's been silent for over a year. Why not stick to the most recent? They'll more likely have a response quicker that way. Then again, there's also the possibility that they do it in order to get more post counts added to their name.
When it comes to being off-topic, I can understand when an individual is new and needs a little nudge. But some of them get off-topic and post their situation right in the middle of something completely irrelevant, like Oreo has stated. It may be because they know not of how the forum is set up and established, or because they're impatient and wants an immediate answer.
All in all, it varies to me how I feel about the ordeal. It generally depends on the experience and attitude of the poster.