Why does my LP fluctuate so much?

It's like a fucking roller coaster....+90 then -90...like what about that is "progression"?

Could you come up with a little better system to put me where I "belong". It's hard to really believe in a system where 4 other people are affecting the outcome of a game and a large portion of the time they are people who are angry about their last game and trolling their next one...

I mean like come on....