From the "things I never knew were a problem" file

The edge of the strap of my beautiful, well-made, comfortable new sandals lands exactly on the cuticle of my big toe.

Friction + cuticle = not good. My morning commute involves probably a total of three blocks of walking, but by the time I got to the office there was blood.

With normal blisters and stuff, I just work through it and after a few days of pain the shoes and my feet come to an understanding. But in this case, I don't know if my cuticles will ever toughen up to the extent needed. (I don't mind wrecking my cuticles and a couple of days of blood and bandaids if it will solve the problem, but not if it's going to be unproductive.)

So the moral of the story: don't by sandals where the edge of the strap lands exactly on your toe cuticle.