Need to be able to block players so you don't play with them at all.

@Bad_Omens_4U 

I am fairly sure you cant stop a player from being matched in the same lobby and personally, I think it would so quite stupid if you could. 

First of all; people would just start to block high elo players either consciously because they dont like getting steam rolled or  because they THINK they are hackers. You say that most people know if they meet a hacker? I must beg to differ. Most average or below skilled players cant tell the difference between a hacker and a legit Predator player, because the difference between the encounter of a, lets say "hardstuck gold" player and a cheater and same hardstuck gold player and a predator is pretty much inseparable. The gold player will die in 0.8 seconds vs the hacker instead of 1 second vs the predator.

Secondly; After a while, when enough people blocked enough of other players,  It would be a "logical" nightmare to create lobbies in which EVERY player in that lobby had NO blocked players with them. Just think about it logically. Player A blocks player B who blocks player C who blocks player D..........etc etc all the way to ...who blocks Player Z... Suddenly you have a situation  where 26 players  cant be in the same lobby and therefore needs 26 unique lobbies just to get into a game. Trust me; it might seem like a no big deal, but it is.