Losing a game until one of your teammates rage quits then you start winning.
I just played a game where my ADC rage quit after 2 deaths and after he left we just started owning the other team so hard 4v5. The other team ended up surrendering after about 30 minutes when we aced them and got their inhibitor and Baron. Some people are just so hard to carry that you are better off literally being down a man the entire game. Maybe its just the mindset of the other team that has something to do with it as well. Like they think its a free win cuz its 5v4 and they don't try as hard to win, while we have to try that much harder. The best part about it is, this was the game that put me into diamond 1. LOL