I think it is probably related to the fact that upsetting your crush has higher stakes than upsetting a random person.

I’ll tell you exactly why this is for me, at least. When you’re exploring a New Romantic option and that person isn’t totally sure if they are into you or not, you can say one wrong stupid thing and ruin your chances of getting with that person. Also with a crush, who usually you don’t know super well, you don’t know what things might be the wrong things to say to that person.

This is why the “don’t talk ask questions” strategy works so well for flirting. It makes you seem interested in them (and you should be) and also prevents you from fucking the whole thing up with your big stupid mouth that meant to tell a funny joke but it accidentally came out racist or some shit.

I think you already gave yourself the answer in your own case:

Because I give zero crap about what other people think of me.

This applies to people that aren't in your inner circle. You want HER to be in that circle and suddenly it actually does matter what SHE thinks of you. You have little to lose with people you don't really care about, but everything to lose with people you do care about. It's an evil social twist that makes everything so complicated. High self-esteem is just the ability to quickly pull yourself up when you fall and the knowledge that you actually CAN do so. It mitigates the risks of "putting yourself out there".

I think it could be being scared of doing something wrong subconsciously.

But what do I have to say here? I can barely speak to a cashier after 30 minutes of thinking what precisely to say and building up the courage, even if it's just "Hello. ... I'll pay by card."

I'd guess that it ultimately boils down to a fear of social rejection and a fear of missing out on an opportunity to mate.

Our brains haven't evolved to keep up with modern society. Back when our brains evolved, social rejection meant we'd be dead. Literally death. That's why embarrassment, shame, and fear of rejection can be so powerful. They could mean death.

As well, we could die at any time. So missing out on a chance for our genes to be passed down to the next generation? Well, we can't die before that happens! We need to make this crush work NOW so we can turn it into a relationship, or at least a mating session, and pass on those genes!

To the point where I straight up leave the room if I see her.

Have you considered the possibility that you are having anxiety attacks? I had a similar situation years ago where I was evading a friend I really wanted to talk to. I had a lot of really awful stuff going on in my life at the time, and trying to engage them in conversation would cause me to flee, and I went out of my way to try to often. In the end I had to resolve other sources of stress before I was able to talk to them again.

Thinking about why you're fearful to ask her out is a way that you're managing to avoid asking her out. Just ask her out OP. You'll feel better afterwards.

Forming relationships are all about risk. If you know this much about her already it's possible she already likes you!

Go for it!

Because you're seeing them as an idealized object of desire, not as a person.

How to break out of this: think of a bunch of flaws they could have that would be challenging but not deal-breakers.

Do you have an idea what attracts you to her?

Do you know how humans choose their partners?

\We usually choose ones that wake up our traumas. It is known emotion for us and looks like attraction, especially sexually. Yeah, we are quite perverse. You know that old idiom "similar to your mother", yeah but not physically or obviously. For me it was that my mother, contrary to what she is saying, hated her father. That also means she hates all man, including her son (me). Keep in mind she is not aware of any of this hate. So until I discovered that, I was attracted to women that hated their father in the same way my mother did. They also hated, and were attracted to, all man. You can imagine how difficult those relationships are.

Go get her, you will have your hearth broken. And it is worth it. But also find some psychotherapist to help you with solving this issue so that next one will be the one that is kind to you.

Its pretty much explained by "breaking the ice" there is a stage of a relationship where both people want it and they aren't sure how committed the other is. This leads to them wanting to take a risk and advance the relationship but fearing the chance of not doing it properly and failing.

From my experience all you can do is take a leap and say what you want to say and after that you can relax and joke about how nervous you both were. Unless you get rejected then you go home and cry in a bubble bath.

I think it’s probably a combination of reasons that vary person to person. I think you captured the big ones, like putting the person on a pedestal and having low self esteem. People are afraid of failure in general, since failing kinda sucks.