Tanks and healers are prime candidates for burnout. Mainly because their mistakes are the most visible.

Tank screws up you either get boss/mobs bouncing around more than a ping pong ball or they miss a cooldown and end up one shot.

Healer screws up and someone dies a horrible death.

Unless a dps does something visibly stupid like hang out in a Landslide, the only way you know for sure they are screwing up is with a dps meter.

Otherwise it defaults to it being the tank/healer's fault.

Years of healing and tanking have taught me this:

If the tank dies, it's the healer's fault.

If the healer dies, it's the tank's fault.

If the dps die, it's their own d@mn fault.