Why Doesn't She Like Me

I was talking to this one guy who was going through an interesting situation. Long story short he liked this one girl, it didn't work...he moved on to another girl right away, it didn't work out. Now when I say it didn't work out, what I really mean is they didn't feel the same way that he did. He was like man, it's the same thing...I did everything right, she should've liked me, I don't understand. Now again, I don't wanna make it seem like I'm frickin Dumbledore or I'm some all knowing wise dude who's been through life and back...but there are some things that I'm pretty experienced in, I guess I would say this is one of those things. But anyways...the guy went on and he was like I was a nice guy, I said all the right things, I was a gentleman, I paid for the food, we went on multiple dates...what happened, she should like me right. Wrong my friend. I used to think that way as well...like completing a level in a video game...if you complete enough achievements, it should get you to the next level (probs a bad example, but it's all I can think of atm), but life doesn't work that way. You can do 'all the right things'...but simply...it's just not there. What's not there you ask? It could be a bunch of things...chemistry, she doesn't see you in that way, maybe she\s just not ready...but I've grown to learn that 'it just not being there' is a pretty viable reason. Sometimes you're just not feeling it, y'feel? As I was talking to this guy, he made it seem like the girl owed him something...whether an explanation or during the time some sort of response of affection. Bro, lemme tell you...I've gotten to the point where I've been on dates with girls, been a nice guy, made them laugh, paid the bill, took them home and that was it...never texted or saw them ever again...why, cuz it just wasn't there. And that's the thing I feel he wasn't understanding. That just cuz you seemingly 'do all the right things' doesn't mean you're guaranteed something in return, nor does it mean she owes you something either. I felt for him, cuz it sucks when someone you like doesn't like you back...but it also takes a man to realize that if it's not there, it's not there and to respect her boundaries. Last thing I'll say is that the worst thing you can probs do is become bitter towards that person because they didn't like you, or even worse become bitter in general because you feel you were entitled to something you weren't.