...You get chainsawed by a guy walking up to you while you're looking at him.
Wall bounce and miss most of your shots.
You have to "pre active reload".
Active sniper.
Active torque.
Hard aim with the shotgun and still miss people that don't wall bounce.
Camp & frag tag/chainsaw. (unless its for fun)
2piece. (UNLESS you're the only person alive on your team against a majority of the enemy team or with sniper)
Wall bounce and still lose to a guy that's not wall bouncing.
Triple melee. (melee twice to down then melee again to execute them)
You run away to active, then turn back and lose to a guy without actives.
Glitch out the map, or crabwalk.
You repeatedly get chainsawed by the same guy.
You get quadrupled meleed.
You go for a free kill in spawn and you don't notice the guy has a shotgun out.
Some of these have exceptions.