k two things:
first, it is a bit bad on rito's side allowing players to requeue right away after a loss / a game full of flamers, yet you can take care of that.. if you go in a new game right away, you will flame - declarative sentence!
next, just remember.. sometimes it happens to screw up on a thing, soo just don't mind it and next time it will be k :p others would flame if a player fails and stuff but.. do you want to do it as well? i mean, it was merely a mistake, everyone makes these.. including your lane opponent right?
ofc, if one is trolling on purpose, go ahead and share your thoughts. But don't go too far.. be fair with him - if he just has a day off, try to cheer him or just make him feel a bit better.. instead of fanning the fire for good..
for the people who try their best to flame though.. you know, i have a friend that noted quite properly: "Oh people are so lame... sometimes, i just keep quiet and laugh at them how stupid they are xdd" ..she is one of the people that are, honestly, normal. and, iis absolutely right, isn't she? :p
just do your best to be the one who you want to be.. and that is it all, really! What is happening around you, doesn't matter so much...