I like multiplayer games and strategy games. Basically I like Mobas. Of the 3 mobas I have played (LoL, Smite, Dota2) I enjoy parts of all of them. What really brings me back to LoL though is the build diversity. In Dota there is one item that boosts ability damage. If you want to carry you have to build aa damage or be a champ who's abilities can 100-0 in which case you just build utility so you can do everything. It is kinda stupid IMO.
Smite limits items you can buy based on your god, plus the 1st person was a bit too strange for me to get into the strategy elements.
League on the other hand has great item diversity and build options. Sure it causes issues like League of Lethality but it also lets me do stuff like AP mid Janna. It also has a very interesting and relate-able cast of characters.
Furthermore League has a great community. Sure everyone complains, but personally I find that makes the nice people stand out all the more. I enjoy playing League and talking on the boards because I get to interact with a bunch of wonderful (and admittedly not so wonderful) people.