1. I found sides to characters in the show that I thought weren't really paid much attention to and I developed these
2. I love 'The Feeling is Mutual' by The DJ Rainbow Dash. I like this because it is focused on TwiDash and I love this couple but I also love the way that this fanfic doesn't try to shove it in my face. Also I like it because it shows Dash's delicate, sensitive side and I love this about her.
3. I love the way that the world of Equestria gives me another place to be when I have a hard time or something like that. Its a great place to escape to and not be bound by the laws of our world.
4.Reading and Writing fan fiction is a great way for me to explore myself and I get to explore my life as a pony and become a different person
5. I don't define a brony as somepny who contributes to the fandom by writing, doing fanart or similar because you cant be exculaed from the bronyhood just because you aren't talented in these areas. But I do think that to be a brony you have to be enjoying and watching either the show itself or the fan work, so if somepony enjoys reading pony fanfiction then this makes them a brony.
6. My Little Dashie is the only example that come to mind, because I don't really read many of these sorts of fan fictions. When I did read this I connected because I desperately wanted Ponies to be a part of my life, either by me being a pony or by a ony like dashie coming into my life.
7. I do like the grimdark themes but mostly I like stories that develop sides of the characters that the show doesn't explain. You could call these slice of life but I guess I prefer that more dramatic ones.
8. If somepony saw me reading a fanfic in public and was interested in why, I would tell them that its a great world to escape to and even though it is a more comfortable place, you feel for the characters and connect to them on an incredibly deep level and this can sometimes make you feel 'unfomforatable' and there is no other fandom that can connect to you on this level.
Good luck with your project...I wish I would get a project like this