I ask myself that all the time. How would it change? A year and a half ago while browsing a forum, a friend of mine (who goes on /jp/ pretty much daily) told me about Touhou. I didn't really understand what the point of it was, and in all honesty, I didn't care for it. A couple months after that, a friend of mine said: "Hey, let's download Touhou Scarlet Weather Rhapsody.", or something like that.
All I knew at the time was that it was a fighting game, and it was actually my first Touhou game I've played at the time. I didn't understand much, but thought that the mechanics were clunky, yet the feel of the game seemed really enjoyable. As I kept on playing, me and my friend formed a network over Hamachi and invited people over time.
Slowly over time, I started browsing /jp/ and started contributing when it comes to wallpapers, or other misc Touhou related images and information. I became immersed in this phenomenon called "Touhou". It seems so simple, right? A bunch of little girls shooting bullets and dodging bullets. How can anything like that be fun at all? You'd be surprised. Give it a try.
A year and a half has passed since then. Over 90% of my music library consists of Touhou doujin (self-published) albums, and that's all I ever listen to now. The music is really inspiring and interesting to listen to, because it can range anywhere from trance, rock, metal, vocals, pop, etc. There's no "set" genre for Touhou doujin music, because it's made by so many artists. There are thousands of circles out there, so you'll always have time to explore.
I still play Touhou too, Touhou Hisoutensoku to be precise. Nowadays, I sometimes frequent #hisouten on irc.rizon.net to look for matches if I have nothing to do. Touhou itself has changed my hobbies drastically. I started collecting figurines, learning different 'research' method whenever I am looking for albums that are in full-blown Japanese, and I honestly don't know a single squat of Japanese. I just find different ways to look up information that I care about. I wouldn't know how to do any of this, if I hadn't gotten into the Touhou Project series.
Because of Touhou, I've also met a lot of really cool and interesting friends over the internet too. I don't have a single regret because of it. It's a great thing to get into if you have the time, because it's not just a game series. It's a culture. \( ^ ω^)/