I'm proud of being a no-life gamer. Any time I'm asked about hobbies, my first and only answer is usually video games.
However, as far as competitive gaming goes, I don't really tell anyone. My close friends know about it, and occasionally I might bring it up if I start getting into a discussion about video games with someone, but other than that I avoid it. My friends respect the fact that I'm generally pretty good at video games, but they aren't afraid to make fun of me for how many hours I have invested into TF2 and that all I ever do is play video games.
I haven't told my parents, other than that I have a "game" and need to play. They're pretty negative about video games. If I told them that I play competitively, they'll most likely take it out of context and start assuming things. They already bitch at me enough about school and how I need to stop playing as much as I do. If they found out that I play competitively, then they would assume that I'm investing everything I have into it instead of focusing on my future.
Most other people don't really understand what competitive video gaming is. They know that it's people playing in tournaments for some kind of prize, but most of them assume that it's in some large event with lots of money on the table that the players travel from around the world to play in (since those are the only kinds of competitive video game events that generally make the "normal people" news). Most of them would probably be really disappointed to learn that the majority of competitive gaming is done in small leagues and played by average nobodies sitting in front of their computers at home.