Winning or losing a game can completely depend on one person.

This is my most recent game (I was in chat with the caitlyn, nautilus, and friends with the malphite who wasn't able to chat)http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2018089671/214906406?tab=stats (I am Ezreal). It was a very close game, but eventually we ended up losing. A lot of the problem was that my ping was 400+ for most of the game and I had trouble positioning in a lot of the team fights, and the malphite on my team had the same problem. With a game this close just about anything can dictate a win or a loss, and it is very easy to see why we lost. Typically I don't blame the loss on a single person because it's a team game, but in this case it was the Rek'sai who lost us the game. For most of our fights reksai dove in way ahead of everyone else and died. The reksai got caught out constantly causing us to have to defend 4v5 mid while the other lanes were pushing against us. I didn't see Reksai with the team after the start of the midgame unless he was dying, and when reksai showed up for the fights he was usually the first one dead so he provided no damage or zone control for me (ezreal) or our adc, and if the enemy frontline got to us we lost the fight. If reksai was not getting caught out and was grouping with the rest of us we would have won no problem.

I'm sure the rest of us did not play as well as we could have, hell I know we didn't, and if it wasn't for my ping being as high as it was I could have completely carried that game (no joke look at my damage dealt compared to everyone else... in my alsmot 2 years of playing this game I have never seen a gap in damage this high), but this really shows that everyone needs to pull their own weight, and that the game can be a win or a loss based on how one person plays.