I'm not having fun anymore

I put in all this work, win my lane, try to rally the team to make good macro movements on the map

and some guy who was placed near my rank and carried by a friend just shits all over it, doesn't care, laughs about it, and moves on back toward where he belongs and I realize an hour of my life is gone, and I have to spend TWO HOURS of winning(not just two hours if i lose again) to get to where I could have been if that player was a bot set to avoid fatal interactions.

this is why making league actually fully team dependent was a terrible idea, and having the best player in the game have the ability to 1v9 was infinitely more healthy for the game. Let the person who doesn't belong move up, or let them abuse rengar top so we see it's a problem and adjust the power accordingly