What is your definition of being too aggressive? Are their different standards for men and women on what is considered an aggressive approach?
My thoughts on being aggressive: You know those car salesmen who always push for the sale, even though you told them you're just looking around - three times already? That's being too aggressive. Granted, it's their job but you get my point.
In the dating world, constantly pushing for some type of "deal" (phone number, email, date, sex, etc.) does not help your chances. In fact, contrary to belief, your chances decrease the more someone says no. I believe the standards DO NOT vary from men to women. It's all based on perception. Some people like a little aggression while others can do without it.
A guy can be turned off by a woman who's constantly flirting with him and not picking up on the "uninterested" signal he's giving her just as much as a woman can be by a man.