The block option and how it doesn't work
If you mute a player in game then for the rest of the game you won't receive another message from that player for the rest of the game. That is until you get into the post game lobby and the option undoes itself and you listen to everything that player wants you to hear until you block them.
However, when you block a player that player will not speak with you for the rest of your time in lobby and any game following.
Now Riot, you always tell your players that you want to improve player's with negative attitudes yet when I block someone from a previous game and they show up not once but twice in a row, all i can say is that you are intentionally trying to create strife. There should be a window of time before you match us with players we put on the block list.
If you really want people to show more team work and create a positive attitude then you should at least grant us that much. My attitude won't improve if the person who cause my positive mood to be ruined shows continuously game after game.
tl;dr Create a system that won't match players who were just put on a block list from playing the next couple games with targeted blocker...