I have a similar story that, when I tell it to my veteran mates (me and my cousin for example play now since 9 solid years!), we all have to "WOW".
There was this very bad Kayn player. His ganks were bad, he died to jungle creeps and well, he was someone you rather wish would disconnect. As Kayn players were so incredibly "toxic" before (not sure what the target group is? Very young male Naruto watchers?) and I am Bard Bard which means I do not talk in ghetto language to reflect my visuals. I kindly said that his skills might leave much to be desired and he just said:
"Yes, I suck with this champ. I can not play him, I don't like him and I will never play him again. Sorry! I will do my best but after that I will never touch im again."
I cried in joy. Every word was right and true. This person was the first that I met since my 9 years that was really aware of it without "no u suckz" or "play challengerzzz men".
EDIT: He was not devastated btw. Nobody flamed him. It was just a sincere guy, honest to the bones but looking forward to a champ he might like more.