My one true MMO addiction in my younger days was City of Heroes, where I was an Empathy Defender (healer/buffer). I played pure support and never attacked enemies at all, because my attacks weren't strong enough to be impactful, and enemies would aggro me and kill me off in 1 hit.
When people asked why I didn't contribute to damage, I explained that staying alive and helping the other 7 people on my team to do 20% more damage and stay in the fight was a much bigger contribution than adding another percent or 2 to damage before I got 1-shot and the team wiped.