The difference between a win and a loss in a game of League should be the least important part of your day.
I'm not saying League doesn't matter at all. You're welcome to invest energy and interest into video games, and attach a sense of accomplishment or worth in your account standing and rank. If breaking into the next rank is important to you, then more power to you! I'm not gonna bash on your priorities. I'm a huge gamer myself.
But an individual match is just that; an individual match. Not something worth losing your mind over. So if you're the sort of poorly-adjusted ass that unloads a tirade of creative hate on somebody for daring to under-perform in your match... expect to hear that it's just a game. Because it is.