Welcome to Elo hell!
The first thing you should know is that a set up of doubble carrys happends from time to time.
From time to time you won't get a jungler or one of your teammates will start jungle at lvl 3 or 4.
People will flame at you since you can't play every single roll and every single champion.
"You're the last one in the team so you will play support or get a report from the team!!!1111!!!!!" Even after you have said that you can play any other roll in the team except jungler and support.
I would love to see any of the really good league of legends players that can play every single roll in the game at there elo level. I don't think that anyone can do that.
People will flame and use really bad language or threat with "connections at Riot games/the tribunal". "Do as I say or get permanent ban!"
People will act like they are 15 year old kids, using racial language. A german nazi word S*** H*** have been used numerous of times. Also sexuall things with peoples mothers, that they'll hack and destroy there teammates computers and desires that people in there team or there family members should simply die is not oncommun

So I say again, welcome to Elo hell. You're stuck with us until next season!