Conventional pretty and erotically mind blowing aren't 2 sides of the same coin (you just have to see the Tulsa sex tape to understand that).
As noladreams said earlier "broaden my definitions of 'sexy', 'fuckable' and 'attractive'. ".
I always had a wide definition of who I find attractive. But In my teens I when on a date with a girl who I was sure wasn't my type. I tried to wriggle out of going back to mine but she was instant. Long story short it was amazing sexual experience she changed my perceptions completely and taught me not to judge so hastily.