There's thing thing called Reticular Activating System (RAS) and outside the biological definitions and aspects of it, it comes down to the way we process i.e. look at different things. It's basically being selective in regards to the positive and negative. Imagine 10 memories about something and let them be represented by smilies. Let's say those memories refer to a day spent in the zoo. The
smilie is a good thing about it, and a 
one is a bad thing. So you can have this: So we have 4 good and 6 bad things. Now, what your RAS can do is choose to focus on the positive ones and even though there are 6 bad ones i.e more, the RAS makes you to think subjectively and close-minded in a way and basically ignores the bad ones. Or it rather lies to you and makes you feel better about the situation, haha.
Now this may be a bad thing but it can also be a good thing, and I'll let you know how it connects to girls. The number 1 and 2 reasons why a guy may feel that he "isn't good enough" for a certain girl is because she may happen to be more attractive than him, and therefor "the problem" is "I'm not good-looking enough, and hence she's not going to be into me". Bullshit guys, bullshit. Of course the other thing is money and/or social status.
Well it's like this. Looks are more of a placebo effect. A guy who considers himself attractive has bought in to the idea that that's why girls like him and is actually confident in himself and believes that the girl will like him, i.e. he assumes attraction. What he doesn't understand is that it's that confidence that is helping more than the looks. Now of course, the Brad Pitts will have it easier than a guy with average looks; but it's more in the sense that he'll get more approached by girls, whereas the less attractive guy needs to approach himself. However, attraction works different for females and males. Guys are more OCD like and are concerned with the physical while girls get attracted more to the confidence and personality. This goes back to tribal life and human evolution in connection with reproduction and survival value, but I won't get caught up in that. Of course, having a great hygiene and being well-groomed is advised. But even that is more for yourself rather for the girl.
So any-fucking-way, if you create attraction with a girl (this can happen extremely fucking easy if you're being your best self, which itself can be very fucking easy if you stop worrying about the way you fucking look i.e. being a whiny bitch) her RAS will start working in such a way that she will focus on your good qualities and basically ignore the bad ones. So if your nose looks funny, she won't fucking care.
Now if you need "proof" for this remind yourself of each and every time you've seen a girl with some douche, looking like shit or even treating her like shit. You must be wondering, man this guy is treating her so badly and yet she takes his shit? That's because her RAS is blocking all the negative bs, and makes the good points be worth it i.e. beat the negative ones. Even though the ratio may be 10:2.
So in other words, stop putting so much pressure to yourself and fill your head with negative thoughts of you being an ugly motherfucker, and realize that you already got what it takes.
Make me proud fellas