PSA compliment your opponents post-game
It inevitably happens. The ADC you're supporting just doesn't work well with your champion or yourself. It's nobody's fault, but he decides to make it yours. Or. Bot is feeding so you can't gank top. This is somehow still your fault. Or. Nautilus jg gets mad at mid for ksing. Or. Someone gets mad at top for feeding when he's only 0/1.
We've all had these games. It means the world when postgame their ADC tells me my Braum (Ez and I were 2/7/0 and 0/7/1 respectively) was decent. Even getting Honorable Opponent can help lift someone out of the funk from toxic teammates last game.
If somebody truly did well, or as well as they could, you make their life better when you let them know. Especially after a bad game.