I noted you asked some follow on questions. I figure you didn't add them to my reply, but I can add my replies to them.
1.If you'd know that the player behind the keyboard is just a little kid, would you still pay attention to what he has to say ?
I don't pay much attention to flamers as it is. I might laugh about them later, but the truth is that as they are not my friends, nor will they ever become a friend, I treat what they say with disdain. The age of the flamer doesn't matter.
2.When you think of your teammates, and especially after they type something to you, do you by chance consider them to be around your age ?
I'm older than probably 99% of the people playing league. I don't expect many to be my age, nor do I worry about it. I've met 60 year olds who have the morals of 2 year olds and 14 year olds with the wisdom of an 80 year old man. I worry more about their emotional maturity.
3.If a player like Faker for example, would be in your game, and it's a ranked game, he plays perfectly in any point , but your team and also you, drag him a bit down and make it hard for him to win , would you understand his frustration if he flames you ? Would you still report him after the game even if you'd win ?
I don't play ranked, as I know I'm not ready. If I was insane enough to try and to end up at Faker's level I'd expect him to be frustrated, but also to be professional about it. IF he flamed me I'd probably just consider it the act of a frustrated 2 year old and ignore him unless he got excessive with the personal attacks.
4.What is main goal of a League of Legends ranked game ? How do you achieve that goal ? Why do you think other players focus on anything else than achieving that goal (like flaming in the chat for example) ?
The goal of any game on Summoners rift is to destroy the enemy nexus or to convince the other team that they can't defend it and should surrender. This is achieved by the teamwork and skill of the 5 players on your side if you succeed.
As for why some people focus on other things. Children are no longer taught how to compete in a contest or how to overcome real obstacles. Many have been rewarded after throwing tantrums in the past, so there is a deep seated belief that throwing a tantrum in game will magically give them a win without having to work for it. I see players who do this as childish and selfish, but it happens.
5.What makes you play a normal game instead of a ranked one and vice-versa ?
I only play normals because I don't believe I'm quite ready for ranked matches. When I do play ranked it will be just to add a new challenge to the game and some intensity. I've run into too many people who are willing to goof off in normals and it can be frustrating to find someone experimenting with some completely outlandish build.
6.Would you like your in game mistakes to remain unnoticed by other players ( meaning them not to say anything about them ) ?
Everyone makes mistakes, and I know I make my share. I'm always willing to type "my bad" if I make a big one in game. If someone wants to point out that I made a mistake I don't mind. If someone wants to berate me for a mistake, I ignore them. I know I made a mistake and will take blame, but don't turn my mistake into a 5 minute flamewar. That's just boring and stupid.
7.Do you accept tips from other players when they give them to you ? Especially after you do a mistake ? Do you tend to get offended by them in thinking that the player assumes he's better than you through them ?
Right now probably 90% of the people playing are better than me. Be polite, be brief and be clear and I'll listen to you. I get a lot of advice from others because I often ask for it. I know I have a lot to learn.
8.Did you ever intentionally tried to lose a game after someone flamed you ? Did you ever intentionally refused to help a player who flamed you during the game ? If you did, why ? If you did not, what do you think about players
who do this ?Nope, not gonna do it. At worst I might play with less intensity and a stronger need to avoid dying which means that I will often be late entering team fights or even fail to show up as I'll be split pushing to avoid being near the person who flamed me. But if I am near and able to help I do.
As for people who do, hate to say this to you, but more power to them. Anyone who flames is going to be involved in a lot of losses as his teammates give up. I don't because I can't play to lose, but I don't blame anyone for doing it. Games are meant to be fun, if they aren't fun because you are being flamed, I can understand you turning on the one flaming you.
9.If someone has let's say promo games to another league, and he's in your game, would you get mad if he's exigently telling you not to repeat your mistakes after you made them ? Would you get mad at him for flaming you if you feed badly ? Would you still think his behavior is unnatural and irrational ?
Unnatural - no
Irrational - yes
Watch any pro sport playoff and you won't see someone berating another player for a bad play. It just doesn't happen. The people who go bonkers because their promos are ruined are hurting themselves. This is especially true if someone "feeds". I've seen one intentional feeder in my games, and he was obvious from the opening moments. Most "feeders" are players who end up in a situation they aren't comfortable with or ready for and they need help, not abuse.
I never think flaming is right, or justifyable. It's a petty act from a selfish person. If you can avoid flaming, you'll find your game and the games of the people playing with you go much better.