I play quite a bit of LoL, and I also contribute to articles on TeamLiquid.net analyzing LoL's tournament scene. I definitely greatly enjoy the game, though it does sometimes bring out the worst in people, it's improved massively over the few years I've played. The tournament scene has also grown, and it's a pretty fun game to watch once you get into it (though the quality of some shoutcasters comes into question at times.)
Co-op vs. AI and ARAM are both pretty stress-free ways to play until you are more familiar with the game (shit, I've played over 1000 games and I probably play more ARAM than I do summoner's rift now.) If that's not enough, playing with friends is another great option - friends are a lot more likely to give criticism in a constructive manner. I'd certainly be willing to lend a helping hand if you want to give it another shot, this time with friends guiding you rather than jumping alone into the deep end.