Just remember this game isn't about always about you, just because you die once or twice doesn't mean your teammates arn't skilled enough to carry you.
-Teamfights can always turn around a game, if you have a team with many aoe CCs, you can win even if you're losing
-If you're losing be patient, try to farm safely and not make plays, unless you know it will work with a good probability
-Yes you might not enjoy the game more, not being in a position to carry or own a high KDA; but imagine if you're the one doing good and your teammates starts feeding, complaining, and spamming surrender
-A game is almost never unwinnable, with teamwork and possibly luck (enemy team throwing) you can always win, or atleast learn how to play under a disadvantage. As long as you take something from a loss, it's not a complete loss
Also, I don't know if it applies to you, but if another player makes mistakes; kindly correct them or don't say anything at all. Saying, gg feeder "player_name" pls report, isn;t going to make him or you play any better. Just try to improve yourself, even if you're the one making the least amount of mistakes, and you will eventually improve as a better player. Plus getting agitated over a player you're probably never going to play with again is just a waste of your time.