Its actually a phenomena, people more intelligent in a field forget that at one point they too were not well versed in that field. If lets say you're diamond 3, and 2 people on your game are diamond 5, thats a decently sized skill gap since higher elos tend to have higher gaps between actual divisions.
So if you are performing at Diamond three, most people are incapable of comprehending not performing at that level, since thats the norm for them. anything below that is sub par, holding them back, and thats where the frustration comes.
The easiest way to not feel this way or not let it affect you is to remind your self 2 core things 1) There may be some factor in the game that is happening or has happened that you have not been able to observe because you are in fact focusing entirely on your game at the moment, and you (and most people) probably only notice the bad things when they pop up, and not the good things.
- You have to lead by example. Even if you don't mean it, if you see someone falling behind, encourage them. On your way to lane give them a "dw you can do this", even fi they dont accept it, you tried. Alternatively, help them. If you're a 5/0 darius eating Camille's ass with a side of butter, you can either Rortate to mid and help make the enemy mid laner more wary, giving your mid more breathing room, or you can start looking around the jungle for someone to prey on, so you can make the enemy jungler less effective in their job.
I wont tell you to tell yourself that its just a game, because lets face it , it really isnt. But you should tell yourself that the consequences of losing arent nearly as bad, statistically, as the reward of winning. Strive as hard for the reward but if things start looking like failure, dont look at the consquences of failing, focusing on soley achieving vitcory.