Remember: Always give it your best shot
Recently played a game as Lux mid. The enemy Darius and Draven (lol just realized) were very fed. We were getting creamed. The Ashe and Soraka were arguing over who fed more in bot lane. And all through this, they were trying to surrender. And I voted no. So this exasperated Ashe asked, "What's your endgame, huh?" And I just said, "Let's play and focus on not getting caught - they might make cocky mistakes."
We ended up winning through effectively kiting Darius, and taking out Draven before teamfights began. When we were storming the base I told Ashe: "My endgame, you ask? My endgame was winning"
Remember, the game may look bleak, and yeah sometimes you won't win. But there is always a chance, especially if the enemy team starts getting cocky (and even more so when you have a late game scaling team versus their early-mid game team)
Good luck in the new season - make those epic comebacks!