Bruiser, Galio, AD Assassin, Fizz, freaking Sylas, anyone. Just don't feedlord the most important role in the game with a champion that you saw do well in the LC$, especially in ranked. Don't queue for a game if you're just gonna run at a Kass with Cass, go 0/4 from pure 1v1's and then literally afk under tower. Don't pick Vlad and play scared like the enemy Zed can somehow kill you and then sit there and watch him gank bot from mid over and over. Don't pick LB, build random crap and then never gank anyone just because your jungler didn't spoon-feed you first blood like not having it completely invalidates your champion.
I have had many losses recently, some of which were my fault but most of which can be traced back to mid being completely incapable of playing mid and yet queueing for it anyway and picking a ranged champion they never even use to boot. I feel deep empathy for those this season who have had to watch their mid 4 levels down from the other mid letting him melee down the second turret at 12 minutes in a ranked match. That is true pain as far as LoL goes; that is something no one can come back from, in-game or otherwise. Please don't ruin games this season just because you can.