The dictionary definition is a little confusing so I will try to make it more understandable for you.
Ever gotten into a debate with someone about religion or politics and that person felt very strongly about their view and was close minded towards considering your view? Ever got to the point where your argument has clearly won against theirs and their response is ‘…no’. This is cognitive dissonance.
Cognitive dissonance is the reason why people find it so hard to change and also the reason why no matter who you were, you would never be able to get frisky with any girl you wanted to. This phenomenon arises because someone would have a fundamental belief about something that they have built their life around to some extent. They have a huge amount of resistance to accepting that they could be wrong because this could shatter their fundamental belief, and then they are vulnerable.
When it comes to changing oneself, we have a fear of something going wrong. This is because you would be living life under a different belief and this is unknown territory. Humans seem to always fear the unknown. It makes sense in terms of survival, you stick with what you know has worked for you so far.
The reason why cognitive dissonance means you can’t have every girl, is because you don’t actually have any control over anyone’s else views, only your own. This is key. The only person that can truly change one’s mind is oneself. I’m not saying it is impossible to inspire someone to think differently, I am just saying that everyone has the ultimate decision of their own in the end.
Cognitive dissonance is also the reason why people tend not to improve themselves. They try to convince themselves all the time that they are actually cool. That they do not want to accept the fact that they suck because then that would mean they would have to do a lot of hard work to get better. Self acceptance is the first step. Just accept you are a big steaming pile of poo, and you can move on from there.
The moral of the story is that after a certain point, you should stop wasting your time trying to get a certain girl to like you back. Instead, you should focus your time on finding a girl who is more ready to accept you for who you are.