Here's my take on Amata and Zessica:
Both are guilty of having quite a bit of an one-track mind... but then again, we are talking about teenaged crushes here. Many teenagers don't handle their first crush well, if it runs into a lot of complications (Amata) or strongly implied rejection (Zessica). And a lot of teenagers haven't had a lot of life experience, so that can make a failed or struggling crush/romance appear more important than it is.
Amata and Zessica both need somebody to take them aside, and talk a bit more sense into them, but that's it. I don't think they're crazy or anything, just a bit obsessed.