Nice guys finish first.
The "nice guys" that "finish last" are just pussies. Most girls don't want an asshole, and most dont want some insecure little boy. It's not surprising they would want someone that at least had a spine.
Be nice and be confident. You'll get the girls.
Also, realize that not every girl you think is hot will think the same about you. There's no point in having your ego crushed because someone doesn't like you. I assure you there are always a bunch of people who don't like the way you look and probably just as many who do like the way you look.