Girl I get on with well is surprised every time I greet or say goodbye to them?

[Anonymous]

I know this girl and I am in love with them. We get on well, we talk regularly. They don't know my feelings for them, and I haven't told them. They obviously don't like me back, because they have a boyfriend. Although the unrequited love hurt at first, I am over it. I want their happiness and them to be happy. I am not searching for love back. I already know they probably do not like me back. Clarifying this due to confusion on a similar, previous post.

We've talked for a while now, for a few months. They'll greet me if they see me, and maybe say goodbye to me. This is a common thing for them to do. The first time they did it, I was pretty surprised.

The other day, I said hello to them and they had a surprised look on their face, and then greeted me back. One day, I once said bye to them, and they were surprised but did say goodbye back. We talk every time we see each other. We get on very well.

So why is she surprised that I said hello and goodbye to her? This has happened twice.

Reposting because of confusion in the previous post.

[Anonymous]

1. "they obviously don't like me back" "I already know they probably don't like me back",
2. "I know this girl and I am in love with them" and "Although the unrequited love hurt at first, I am over it."
which one is it? You're contradicting every statement you're making.
She has a boyfriend, and you're over her, yet here you're trying to decipher her facial expression to look for a meaning. That's probably how she looks when someone greets her because she probably wasn't expecting it, or thinking about something/doing something and your greeting surprised her a little.

[Asker]

I apologise for the contradictions. What I was trying to say is, they don't have any feelings for me, but I am over this.

I know I am deciphering it and maybe that shows I am not fully, fully over it. But I am more over it than in the past. I just wonder why the surprise is there, that's all. I am not looking for a meaning like love, because I know they don't love me. So I just wonder why they have some sort of surprise sometimes.