Try to switch to healing for a few matches. You'll see so many things from a new perspective which you've never noticed as a tank. Melee line-of-sighting and die because you can't heal him behind the wall. They blame you! Enemy dps and tank bursting you with damage and status effects and you get zero help from your teammates, like stuns so you can recover. You die and they blame you! Marking you as ignore and spamming Nice Job. Hmmm, maybe that lost is not entirely healer's fault if his team don't help him. Because that's what usually happens.