I have become more outgoing and friendly. I like to share the fun and happiness with others. Also I have switched from writing My sad, creepy horror stuff and have a killer fanfiction going with my OC's. So yeah It has been a good thing.
I feel like after joining the mlp fandom, it widened my perspective to understand that people like different things and it should not bother me. I have always been a nice guy and I think the show has taught me many new thing that I would have never even thought of, making me into an even better person.
Thats the most common thing I've heard from most people. There's been a lot of stories about people's lives pulling complete 180's and having their lives saved and such. Its amazing to see what community can do.