On the subject of opening doors, I hate it when ppl make it into a gender issue - I open doors for everybody if I'm near the door and would expect anyone to do the same for me (not in a 1940s Hollywood style, but just if you see someone coming and it would be rude to let the door slam, you know?).
On your subject, Ash, I agree that it is possible to be too kind - not just with girls but generally in life. It's about the fine line between kind and a pushover... I think its because people are attracted to people with self respect and self confidence, and if you are constantly attentive about other people to the point that you compromise yourself, it can be perceived that you have no self respect, in a way. It's that phrase 'generous to a fault' - you can give too much sometimes and I think people are suspicious of that sometimes eg the poster who referred to the 'puppy' boyfriend.
It's all those good old fashioned concepts, I suppose - treat em mean, keep em keen, playing hard to get etc - oldest tricks in the book, but they still work, for boys and girls.
I think the secret is to stay the kind, generous, sensitive lad you clearly are, because a good heart is worth everything in the end, but just be careful about how you reveal that to certain people, if that makes sense. Women don't really like bstrds, they want good, true qualities, but everyone is intrigued by 'antihero' qualities sometimes.
Best advice tho is to not change yourself intrinsically; you are who are and people will always respect that. It's just maybe the impression you create you need to work on - if you've offered to go out of your way for someone a few times, then just be careful you don't get taken advantage of and have ppl think you're a mug. You get what I mean. Btw, love that you do martial arts n boxing. Nice work! Good luck with the girl. If it's meant to be, she'll say yes.