This may be sacrilege, haha, but when I was little my sister used to tell me to pray and think about Jesus when I woke up from bad nightmares. But it didn't really help. So she (being a clever sister and loyal Whovian) told me to think about how the Doctor was pretty much invincible, and good, and saved people. The nightmares still came, but most of the time I didn't even have to wake up, because I was able to insert a Doctor-esque character onto the scene in my dream and it turned out pretty wonderful.
Anyway, has the Doctor's character done anything in your real life?
Not trying to start a religion or anything.
Not only has the Doctor taught me that it is okay to be afraid, but also that that fear shouldn't stop me. He taught me to be impulsive, but in a good way, like more active. He is always running somewhere and on an adventure, and I strive to do that as well. I don't really know if I explained this well but I hope you understand.
He thought me to be excited to the ordinary things that happen in my life. That how the everyday moments, the habits, everything, is brilliant, wonderful, and beautiful. He made my mundane life look like an adventure, and now I want to do an actual adventure to see how much more awesome it can get.
He's mostly just inspired me to be more adventurous
I don't think the Doctor had really changed anything about me but he has given me something to be able to find other people with.
The Doctor taught me that even though life can be impossible, you can still at least try to do something instead of setting around and let everyone else deal with your problems. Just because you are confused doesn't mean you're helpless. I also finally understand time travel, which has been confusing me since I was little.