I'm not sure if I've given this impression, but for me "normal" means "average, widespread", not "healthy" or something... Although I actually don't know if it's really normal, or it's just a vocal minority that I'm familiar with... On the other hand, even if I don't backseat-game, often watching game videos makes me kind of sick when I'm interested in playing the game and the person isn't playing the way I think the game should be played. Of course, I just turn the video off.

It's also been a learning process for me to remove from my life video games that could negatively influence my relationship with people, such as yelling when I get upset.

I mean, take that as you want. Video games are at this point scientifically designed to pull at those strings - possessiveness, perfectionism, etc. I don't think it's at all surprising that unpleasant behavior would be widespread.

Of course, it's a different matter if one is able to identify these tendencies in oneself and confront them.