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Spy, because he's the most fun to play and I'm secretly a masochist, but I will play any class that my team needs at the time, which mostly means medic.
As someone who plays a lot of pyro and engineer your class is either my worst fear or the easiest mu possible lmao. Same on the Medic thing, it's amazing how little casual players care about basic team comp
Weirdly, you are entirely correct, but not for the reasons you probably think. I actually love playing against pyros because you're always so confident that we're a free kill that it's easy to get you to chase me and pick you off with the ambassador.
and I'm secretly a masochist,but I will play any class that my team needs at the time, which mostly means medic.