It was worst for me. Most of the times he killed me right after I spotted him. And he killed poor TK once or twice just for following me. And being a Medic.
Also, for the longest time I've never gotten Dance, Dance, Immolation, the Pyro achievement that asks you to provide a deathcam for each of your weapon taunts. Basically, I had 2 out of 3 and I couldn't tell which was left, and I eventually forgot about.
Pariah goes and kills me right after I hit him with a crit flare. He's burning out, doing the shotgun taunt. He dies while I'm still respawning, and I get the achievement. Crazy bug. But thanks!