This happens to me too. I can't really get around it no matter what kind of mental gymnastics I try.
I always stick to playing my few main champs every time I get a craving to play league. Otherwise I just don't play at all. Even if I turn off chat I hate being "that guy that fucked everything". With my main champs it's very rare that I feed my ass off embarrassingly.
This is something that I noticed as the seasons went on with league. As the game balance became less crazy and pro play became more widespread, the proper way to play also became more chiseled out. Everyone wants to emulate pros, emulate streamers, or just get an ego boost out of being great at the game. People raged back then all the time, but it wasn't as bad imo. Apart from getting mad at the fact you were losing people didn't care so much about your builds and champ picks etc. Maybe I'm looking at it through rose tinted glasses but I think the growth of the game and pro scene at the very least destroyed the fun quirky league of legends.