What is one fact about Romeo that disturbs or bothers Juliet?
Difficult one. Obviously, to begin with, Juliet is distressed that her husband is a Montague: "why are you Romeo", she asks, in the famous lines below:
O Romeo, Romeo! wherefore art thou Romeo?
Deny thy father and refuse thy name!
Or, if thou wilt not, be but sworn my love,
And I'll no longer be a Capulet.
But she soon gets over that: as Friar Laurence comes up with the idea that a marriage between Romeo and Juliet would heal the rift between the Capulets and Montagues. A negative quickly becomes a positive.
After that, I can't find a single example in the text that suggests that Juliet is disturbed or bothered by anything that Romeo does or says. Even when he has murdered Tybalt, for one second, she thinks that Romeo might look great, but be awful:
Was ever book containing such vile matter
So fairly bound? O, that deceit should dwell
In such a gorgeous palace!
And then, in the next two speeches, she's back on side. And she never criticises him again:
He was not born to shame.
Upon his brow shame is asham'd to sit;
For 'tis a throne where honour may be crown'd
Sole monarch of the universal earth.
O, what a beast was I to chide at him!
So the one fact is that he's a Montague - and that goes away. The fact that he's also a murderer doesn't bear any more consideration, it seems. That's love for you!
Juliet obviously dislikes the fact that Romeo is a Montague, coming from the family that her family hates the most. But on top of this Juliet does criticize Romeo’s rash decisions. After Romeo kills Tybalt and is banished, Juliet does not follow him blindly. She stands by him only after considering things through and knowing that Tybalt would also have killed her husband if given the chance.