Include the particular lick/song/player that makes you want to master it.

I would love to master IA's (from http://www.freakkitchen.com ) use of natural harmonics... I mean that guy knows EVERY HARMONIC'S PITCH!! even the ones you find at the bottom of the neck, like Jaco Pastorius used to do!! So he makes his guitar sound like a whammy, but without a whammy... And he plays entire solos with harmonics... Not written out ones, he improvises!