What do people think of being attracted to someone and losing interest immediately after she reciprocates?

Heres some context for my scenario:

There was this mixed gender class, I was close to/ familiar with all the girls in there.

I was rather bored with getting close with girls already as it seemed fairly repetitive. However, I felt rather attaracted to this girl that didnt respond as well as others to my attention.

My attention became drawn into her. After a while she finally seemed addicted to my presence and I immediately lost all my interest. What are your thoughts on this?

In hind sight, I think my success was due to my friendliness, confidence and non-neediness. Furthermore as it was a class context, it makes it easier to open up. I talked to girls who were generally more extroverted at first. The rest of the girls can then see the attention they are lacking and makes it essier to open them up. I am basing this on the book The Art of Seduction.