why i play ranked once a month

on my main this game is cancer. why did we lose with such a big lead all game? oh yeah the vayne goes into their jungler and decides to get caught died 4 times in a row within 30 seconds of being alive, malphite did the same 3x in a row blew ult and flash still dies. diamond 5 just gonna let it sit there because why play ranked? i do good enough to win i just get players who are boosted and have 0 positioning and just wander and die! https://gyazo.com/7a219e6baf231fb76a9a2b2ee367d374 https://gyazo.com/c828850460984017556aa2c122fcb4d1 why play a game if i deserve to win yet still can lose because one to two players cant do something as simple as join the team and not go on their own?