Think about it this way anon(s); everyone you know has at least a few things that piss you off. Now, realize that, were you to get closer to your oshi, there would be things or habits that piss you off about them. Now realize also that, being you, there will DEFINITELY be things about you that piss them off.
Think about how she's going to have the audacity to constantly bring up your (subjective) failings when you (because you love her) either bring hers up as little as possible (because you know she'll get defensive about it) or are gentle in your complaints.
In the event that she DOESN'T do this, you just KNOW that your oshi will stew about it and do the whole "Hmm? Nothing's wrong" bullshit when you ask, pissing you off, because how are you supposed to have a dialogue like that? You will ask yourself why they're acting like children.
Suddenly, your mutual friends start acting a certain way until one of them tells you privately that she's been talking behind your back, which is some bull-fucking-shit because YOU never do that (even though God knows you've been tempted).
So then what, are you supposed to just act like nothing happened when you get home? She still won't tell you what's wrong (lol, actually imagine) and honestly? At this point, you're done asking. You have better things to do than babysit the feelings of a mental child who can't say 2 words without being passive aggressive, even first thing in the fucking morning.
Eventually you'll realize that all in all that time you spent pining after her, you didn't know her. The REAL her. The manipulative she-devil who feeds on the pain and anguish of flawed but ultimately innocent men...
TL;DR, your oshi isn't all that she's cracked up to be
