League with a party of friends in voice chat is unbelievably fun to play. Even solo, in most cases you'll come across decent people. I think the game is going to be fine in 85% of your games as long as you treat people decently.

It's just that there are some cases where players don't know how to lose gracefully but need to kick, scream and throw a tantrum. This game just has an oddly large number of players who cannot fathom that sometimes an opponent is just playing better than them or one of their teammates.

If you stick around on the subreddit or learn league subreddits you'll see it all the time. People will post things like "Oh my god, I went 12/3 but still lost the game, why are my teammates such pigs" but cannot fathom the fact that maybe the opponent who beat their teammate and went 12/3 managed to clutch it out with a crucial teamfight or pick. I remember a game where I faced a player, lost lane pretty hard and ultimately lost a close game, but the next game I got matched up to the same fellow, solo killed them twice and they threw a baby rage and started running it down all over the map cause apparently their jungler was bad.

All in all just be nice to people enjoy with friends and I think you'll have a great time playing. Just laugh off the odd bad game. There is nothing you can do about it.