For BB, and CoCo, and all the girls who have posted "Why don't nice guys like me, what's wrong with them?" threads in the last week or two: I can tell you exactly why "nice guys" don't approach you, but I can't do it in twenty words or less. There's not much point in trying to answer your question, then, so I'm only going to hit a couple of points.
First, the assumption that there's something wrong with men because they don't pay attention to you is a self-defeating attitude.
Second, many guys avoid a "cold" approach to an attractive woman, because they know from experience that most attractive women are completely wrapped in self-approval, and will immediately reject anyone who fails to meet their irrational expectations. This is of course not true of every attractive woman, but most men's experience shows that it is true of most.
This is, of course, unfair to the lovely ladies who post on this forum, and who are models of sweetness, understanding, and approachability. But, life is unfair.
None of that tells you anything about your individual situations, does it? Sorry...best I can do right now.
When in trouble,
Or in doubt,
Run in circles,
Scream and shout.