This misconception plays into our perception of the opposite sex significantly. Consider how frequently you change your behavior towards the men in your life…
If I approach a girl in a bar awkwardly, and then speak to her in a low voice because I am nervous, she isn't going to be attracted, and isn't going to respond well. The fact that she is short with me, or excuses herself immediately to go to the bathroom doesn't mean that she is a "bitch;" it just means that I didn't attract her enough. The next guy who approaches her might approach her confidently and genuinely, and have her wrapped around his finger the rest of the night.
If I have a dead-end job and lack ambition, my girlfriend isn't going to respond to me in the same way as the guy she dates next (i.e. after she dumps me), who is intentional in his career and gainfully employed in a position he truly enjoys. I might tell my friends that she was “cold” or “distant” but they'll know as well as I will that her next boyfriend probably has none of the same problems. Or maybe she is the one complaining that he is cold and distant.
The same kind of girls that ignored me when I was young and lacked confidence now treat me entirely differently, because I am older and far more sure of myself. At twenty years old, it was tempting to view those girls as stuck-up or bitchy; but the reality is that they were probably acting like angels towards some 30-year-old who was much more attractive due to his age, maturity and position in life.
I am not saying all of this to make a point about women, but to make a point about men – because men work exactly the same way. It is easy to believe that a certain guy is an asshole because he dumps you without an explanation, or that another is an authentically nice guy because he treats you well. But I am telling you: those men behave in entirely different ways with different girls.
The guy who you think is a player because he hits on three other girls before taking you home, then never calls you the next day – I guarantee that he is genuine and respectful and serious with other girls he dates. I know this because I've been that guy plenty of times. Some women I treat well and with respect, and others I don’t. If I see a girl I'm attracted to and whom I respect, I change my game completely. My male friends do the same.
The guy who is a dismissive asshole to you is a babbling, nervous idiot with the girl he is crazy about, and the guy who is such a gentleman to you absolutely crushes the hopes of girls that he doesn't find attractive, or doesn't respect. Likewise, the guy who never calls you back isn't “flaky,” he just doesn't care that much about you. I am sure there is a girl out there who has complained that he was needy and contacted her too much. And I am equally sure that the guy you were dating who seems to have “commitment anxiety” has at some point in his life practically begged to be in a relationship with a girl.
The thing is, nice guys don’t exist. “Douchebags” don’t exist. The behaviors we describe with these terms are not innate and static characteristics of any given person; they are behaviors that change depending on the other person involved and the circumstances surrounding the interaction. Of course there are men out there who are more disposed to certain types of behavior than others; but the degree of attraction a man feels for you will affect his behavior towards you far more than anything intrinsic to his personality, and the degree of attraction he feels for you is significantly affected by the kind of behavior you'll accept from him.
So instead of complaining about the dearth of nice guys or the abundance of douchebags, start thinking about what you can do to make then men in your life treat you the way you want. Because that is what is going to make the difference – not finding some "perfect guy" with some supposed personality type. You don't find perfect men, you elicit perfection from men.