Due to my dislike of the meta-game and communities in MOBAs I ended up stepping away from League of Legends for a long time. It took the introduction of ARAM (All-Random All middle) mode for me to enjoy them again. Randomized characters destroy the idea of a meta, and it brings the game back to focusing on having a character and fighting enemies rather than placing the importance on arcane jungling routes, last-hit numbers, and team composition.* It is by far my favorite mode because its very design helps reduce much of the stress of being in a typical MOBA game; players can't expect you to know every champion when you had no control over who you got and with the amount of chaos going on things like creep-score have diminished importance.
But for all its perks ARAM still has some points I find unduly frustrating that could deal with a little tweaking.