I think about toes. I love the bony parts of people's bodies, including hands and feet. The knobblier the better. This lovely pair belong to my friend Lily's boyfriend, who was kind enough to sit still so I could draw them. I'm completely in love with how long his toes are, it's like an extra set of fingers!
Tragically, this one is mine. Those are blisters. If shoes are designed to be worn with socks you really should wear them with socks, as it turns out.
(Yes, I sketched my blisters. What else am I supposed to do after 3 years of art school?)