That's exactly the thing, you like her, she's "alright".
Not many are passionate about her.
Since Cara sometimes spends weeks without seeing the MC, i'll say it's natural that when they meet they wanna make up for lost time(applies to Nikki as well).
Also important to note in this Cara vs Layla comparison that Cara lost her virginity months ago and had sex numerous times since(maybe more than the gallery shows, since there's a time jump between the first time and the last one before the MC moves to MS).
Layla just had her first and second times a few days ago, she's still spreading her wings.
Talking of sex freak she just lost her virginity and might be planning her first threesome(not that i'm complaining), the girl is gonna be crazy with a little time.
Alexis relationship starts sex first, get to know each other later...
Then becomes a bit all over the place, weird mix of sexually aggressive yet sometimes lacking confidence and experience... never brought a guy home(but brought the MC day 2), mile-high club girl who has never sucked a dick.
Various girls show clingyness and extreme attachment(sometimes sudden) at various points, it's hard to gage which one is "winning".
I just know it's not Tori 

Celebrate 
Kaskaze