Ranked matches

Why does it seem like people in ranked matches aren't serious and try to ruined things for other people. I'm getting to the point where I'm about to stop playing cause the people in this game are irritating. League of legends probably has the worst community ever where people get into ranked matches and purposely lose for everyone else. This happened to me 6 times in a row and I'm tired of it! I wanna move up in the ranking not move down cause someone wants to get a laugh out of it*[sg-ahri-1]*