The first obnoxious category is the Philosophy 100 Kid - These larval bedwetters may have prematurely ejaculated egos because they were able to get into the college of their choice, especially if its a community college. They don't know shit, but they will go out of their way to show you that they do - after all, they are armed with the knowledge of the 9 or 10 logical fallacies they learned from Far Side cartoons their professor had to show them at age nineteen because they were too stupid to understand those cartoons when they should have been reading them at age eight.
The Philosophy 100 Kid will look for posts of arbitrary complexity, scan them for the handful of logical fallacies in their puny mental database, squealing and wetting themselves when they find a match. They will immediately respond, pointing out the fallacy by name. They may not even be accurate, or they may miss and ignore the rest of a well-reasoned post, or they're just too damn dumb to do anything except regurgitate what they're taught in class. But that's it. They offer no alternative ideas, no real challenge, not even a "haha dumbfuck" response that some may consider worth reading.
The second obnoxious category is the...shit, the first is all I have for now. Maybe more later.