On the opposite end of the spectrum... players that don't put some objective, thought, effort and game knowledge to their builds are insufferable in GW2. You end up with situations like this and this where you're putting an unfair burden on other players because you can get away with it, plain and simple.

In a lot of situations people are sympathetic and understanding when they feel that you've made a decent effort. The problem with a lot of the more casual player-base that wants to do end-game is that they do not put in an effort to learning how the fights work, they get F'd over by mechanics which are designed to disrupt their rotations, and then they do mediocre damage.

Most people that I raid with are fine with like 10-20k DPS from a beginner (vs. a 30k benchmark). The problem is when you're doing like 3-5k DPS AND you're screwing up mechanics. There are people that things too far, but there are also people that don't put 15-20m of practice into their builds and wonder why they're getting kicked/replaced.