Gamers take games very personally because it is what defines them. We are what we eat. In most cases gamers get very emotional (anger and stress mostly) when playing a losing or imbalance game. The question is why? As an observer, it's hard not to be judgmental when looking at people who swears prematurely while playing games. I used to be (maybe still am) one of those people who swears and curses the gods (mostly Zues) in DotA when I'm losing. It's funny when you look back.
People are angry for a reason. Nobody likes to lose. But why so serious when it comes to games? The first obvious reason is games mean a lot to gamers, or should I say, that game means a lot to that gamer. All gamers have their favorite game, the one they put enormous emotional effort into when playing. They are defined by how resourceful they are in-game as opposed to in real life. If I were training Tekken for many years and lost to some newbie who spams buttons in a ranked tournament, of course I will be emotionally compromised. Who wouldn't?
The second reason leans heavily on how competitive that gamer is. Competitiveness is double edged though. It can push for improvements (game knowledge, reflexes, teamwork) but also make you too emotional over something intangible. That is what separates the gamers and pro gamers. The professionalism in pro gamer means they are really good at their roles in their games and they are good at containing stress and pressure levels as well as their emotions. That's what make games a good sport sometimes. Game tournaments are held all around the world for popular games and some even made careers playing as pro gamers.
So the next time you hear someone raising their voice while playing a game, you know how much emotional effort is being poured in.
