Finding excuses when we lose online is something we all sometimes do. It can be frustrating, after all. Tutorial Central collected a fair amount of StarCraft II-related ones, but most of them would apply to any competitive game.
Here's their clip below:
It's hard to argue with these (here's an example of someone who can't compete when it's too hot), but I'm not sure about the last one, number 46. Skip to the end and see for yourself. That's an impossible one and I'm pretty sure it never happened to any of us.
Also: #47 - map hacks
Starcraft 2: 46 Reasons Why You Didn't Win [Tutorial Central Sc2, YouTube]