Colyne Effect
When a guy is attracted to several girls but he isn't sure which one is the right one to be with. The girls like him in varying degrees but they are all attracted to him. It's a double-edged sword and a struggle for everyone involved.
Eren : You see Armin with his new girl?
Mikasa : Yea, it's the Colyne Effect. That's the fifth girl he's started talking to.
Mikasa : Yea, it's the Colyne Effect. That's the fifth girl he's started talking to.