Do you belive ghosts

Okay, let's say that a few months ago something happened and your reflection in the mirror was a little different. Naturally, it freaked you out.
After that, you were afraid you'd see it again, wether it be consciously or subconciously, because you were sure there was something weird about it. Because of this, your mind projected the image of this "Ghost" onto the mirror, even if it wasn't really there, and the more you saw it, the more you were sure it was there.

To be honest all of these questions and theroys are confusing me now.

How exactly are they confusing you?

All Tony & I have really said was that you may have once saw something that freaked you out/confused you & everytime you looked at the mirror, whether consciously or subconsciously, you on some level expected to see that something again. You mind was in a state of anxiousness & preparing itself to again see it, and therefore when you looked, your mind was keyed up, you saw exactly what you were afraid/didn't want to see.

It's something thats quite common really, especially given unexplained occurances - I don't have any websites or what have you really to back up what I've just said, just that back in school during history class, we did a small project on the history of unexplained phenomina (sorry for crappy spelling) in New Zealand, and there were a lot of instances were someone saw something & became so scared or nervous etc that their mind & imagination went into over-drive around the same time/place they saw whatever it was & thus could have been the reason why they saw whatever they saw again & again, at the same time/in the same place.
That's all, hopefully that cleared up the confusion.

As an atheist and rationalist, I feel the idea of ghosts is absurb.

I study was conducted (pardon more lack of source) with two groups of students. Both involved the same abandoned movie theatre. Group A were told to observe the theatre and look for areas where renovations should happen. Group B was told the theatre was haunted, and that they were looking for ghosts. Group B reported that there was spirtual activity going on, while Group A reported no activity of that sort.

In conclusion, I feel it is more of a physclogical idea. If you think there's going to be ghosts you may then trick yourself into feeling, hearing, or seeing ghosts.

Regarding the mirror: Without seeing it myself, I can make no conclusions, but generalizing from most stories of this nature, I can make a great guess. That being, it's just a flaw in the mirror which looks vaguely like a face. This is called Pareidolia. You saw it once, made an image in your mind as to what it was, and from that point on, it was only that in your mind. I'll give you an example from my own life. My shower has wood trim around the entrance. On the side by the shower head, there are several knots, one of which I though looked kinda like a caricature of a toucan. Now, every time I take a shower, I see the "toucan".