Need to find a good game.

Grab the Jedi Knight Collection, its cheap right now and the games are really awesome, jedi outcast and jedi academy have an active multiplayer, you can download thousands of mods, maps and extra stuff for they and the game its really cool, you should try it.

I saw you played a little bit warframe. Maybe try more, it's hard to understand all the mechanics at the beginning but with some practice and if you play with friends, this game is fun imo.

cod MW3 OR bo2 or CS:go

Um... Borderlands 2? It is co-op/single player though, not competitive multiplayer.
For competitive, any fighting game (though I personally recommend Skullgirls) if you have the patience and stubbornness to not give up. If you don't, then how about Awesomenauts? :)
(I'd say looking to get addicted to something isn't very healthy though. :P )

Any MMO suggestions?

Hammerwatch! Super addicting, especially if you play with friends!

Dungeon Defenders is pretty fun with friends.

Well if you like puzzles then Portal 2 might be one of the best options out there. The built-in chamber creator and steam workshop has given me hundreds of hours of play-time.

Try the fallout games, they're pretty cheap right now, hold up well, are addicative and you can put a few hundred hours into each of them. Though they aren't mulitplayer

You play a lot of CS:S. Why not CS:GO? Plus CS:GO has item drops, so it pays for itself fairly quickly.

Dungeon Defenders. Rpg system that is incredibly adictive, can keep you forever. Seriously.

My favourite multiplayer available on steam is Arma 3 or arma arrowhead with ace and acre mods.

payday 2