Wow its hard to choose just one reason.

I'd have to say I enjoy the fact that it can make almost ANY situation better.

Movies? Fun
Movies high? A blast!

Sex? Great
Sex high? Fantastic! Like a close encounter with Jesus.

Music? Awsome
music while high? orgasmic!

Going to the DMV? Sucks
Going to the DMV high? Not so bad. You can make fun of people and laugh.