I can imagine that all of us went through lots of "report" threats during champ select and in the game. 90% of players start flaming for reports without any reason, sense or understanding for their teammates. When someone says "reported" in champ select, I wonder "for what will he report me, picking my champ? But that report doesn't exist". We only have a hand full of reports, mostly used "Intentional feeding, Verbal Abuse, Negative Attitude and Leaving game/AFK. "
Another example would be if you loose your lane and opponent gets fed, teammates start to shout "report for feeding", but the report is called "Intentional feeding". I did not feed intentionally, my enemy was just better than me or I got overganked. I tried my best and I couldn't avoid the deaths, I say that I am sorry for that.
These 90% hotheaded players need to get the difference and learn the understanding of reports and why they exist. They exist to punish players who are actually verbally abusing their teammates, who do intentionally feed, who intentionally leave the game. They don't exist for you to express your frustration of defeat.