This is what I have to say...
I hate it when people on the losing team or in my team yells out
"OMG this team!!!!"
"./ALL Report this Noob for feeding!!!!"
Especially when they are doing just as bad. I mean, that person could be a good player that just having a bad game.
I also do not like the fact when people just want to try out something different and one of our teammates rages at that person without giving him a shot at it.
like there was one time on my team there was a Ashe on our team wanted to go support.
The Jungler was raging at him for doing bad mainly because of doing Ashe support.
I thought the dude was doing pretty well for his job maybe could had done better but our Jungler was just plain mean and raging at him without giving much explanation.
There was also a few times other times when someone want to try out something new and before the game even starts they say something like...
"OMG...WTF!"
"Someone please dodge this game!!!"
There are times where I get mad myself when I have a player feeding but I do not rage at them like most people do in my team.
I try to keep my calm,play like I usually do as a team and do my best to win the game.
Sometimes I even friended the feeder on our team because he turns out to be a good player and dominates the very next game.