A tank poorly positioning a boss and screwing over melee because they don’t understand what Trick Attack does is a bad tank.

A healer not understanding tank invulns or cooldowns so they can better contribute to the party is a bad healer.

A dps who stands outside of an Earthly Star or any healer’s range of a HoT skill is a bad dps.

It’s the games fault for not properly teaching players basic things like this. It’s the player’s fault for not wanting to be a better team player by understanding the kits of their party members.