The Danna Effect
When you notice that someone you don't really know has been looking at you(like a lot) and you start wondering if they like you. This in turn makes the possibility of them liking you exciting and you develop a crush on them. You give them attention because they gave you attention. Named after a friend who is struggling with this high-key.
I noticed she started liking that guy she said she had eye contact with, totally the Danna effect.