26 here,
TBH I think I am growing out of gaming.
I started when I was 4 and have played ever since.
I'm not sure what it is, I think there are a lot of reasons:
Lifes priorities have changed I have a kid so he takes up a lot of the spare time I used to have for gaming,
The games don't engage me in the same way. There used to be a time where I would play a game to absolute death, I would literally spend every waking second thinking about it, and when I was at home I would be working to completion. Now gaming somewhat feels like a chore.
The online Aspect is starting to bore me a bit too. Back when Halo2 came out we had plenty of people online from these forums and we made other friends by association, over the years. I could log on at any time and I would have a great group of friends to play with.
When GRAW came out on the 360, the games were always over-subscribed, we all had a great laugh and despite not really thinking too highly of the game I enjoyed playing if because of the people. The same could be said about GoW.
Halo 3 is the game I currently play and tbh I don't feel the same way about it. I just find playing Halo 3 stressful it seems every game is full of whining moaning and arguments. The only time people enjoy themselves in Halo3 is in a Rocket Races game, which we cant have very often because we never get the numbers up.
I have taken several hiatuses from gaming over the last year or so. The first one was to complete my degree, during that hiatus I really missed gaming, but subsequent hiatuses which I have spent reading, or watching TV series I have not even been that bothered about gaming, I've not come home from work in months thinking "I cant wait to play this game"