One time I had a guy jungling (he was doing everything wrong) and when he smited red instead of trying to steal dragon with smite he replied "I smited red to get to dragon faster" How about everyone else? And no mundos ulting themselves.
"Why would you play a champ you don't like?"
In ARAM.
I asked my jungler if he understood that the LeBlanc that was running in the stupid direction (which he was chasing and "killed") was the fake one. He said yes, but he wanted the gold. Meanwhile, the real LeBlanc escapes with one hit left on her.
I was playing 
and had bought a 
I start using the stacks up to kill minions and get both me and my ADC gold, then my ADC blows up at me for getting creep score. She said something like, "Stop killing the minions! You're pushing the lane!" If I'm not mistaken aren't you supposed to push the lane to get the tower and supress the enemy ADC? And wan't my ADC supposed to be killing minions to gain gold as well?
Someone said in /all on the opposite team
"Report mundo, he ulted himself instead of me and I died."
pretty sure it was a troll but
i laughed
But know that I see you wrote that, I will do something else.
We were taking baron and the master yi went in and smited it, then left. (It was half health)
He came back right before we finished and pressed W.
few minutes later he got executed by dragon
Just had this one happen yesterday.
"You can't lag. We're playing aram."- Miss Fortune
She was harassing our lee sin for doing poorly. He said he was lagging. Then that happened. I called her out on how stupid that is and she responded exactly how you would expect.
I was playing a ranked game and the enemy 
kept ganking top lane and only top so i asked why and he replied with "You don't gank a losing lane." Keep in mind he was their jungler as was i for my team and i was playing 
Back when there was a mastery that reflected minion damage, I happened to take a blue buff that I was trying to gift to my midlaner. He raged at me for that, I just laughed at him.
In an aram I had someone go off on me for buying AD on WW. He was like "WW ult does magic damage!" I said "but it scales off ad" to which he exclaimed "you are so stupid, magic damage scaling off ad yeah right!" (or something like that) The funniest part was he got a few others to agree with him. It was a great game=)
"An inhib turret isn't worth dying for." ~ Zed, 1 auto away from destroying an inhib turret 5 seconds before the enemy spawns. I had to TP on the last minion when I respawned and suicide for that one auto-attack just to clean up his mess.
Runner-up:
"Sona is still playable."
