A great reason:
cuz they think each other are great kissers
An even better reason:
Because he respects her shakira. 
this may sound bad but:
Because when she's going to find food, he's going to pee., lol i got that from her unscripted.
Because she LOVED the Mind the Gap concert she went to.
Because she said he's hott.
Because she knows the song that's playing in his head.
Because they both love the red hott chili peppers
Because they both love to sing and play the guitar.
Because he can carry her.
Because their kisses are so hott.