These metallic Alexander Wang shoes have a sturdy enough heel to stand on for hours, but the little strap across the toes is so thin, it sometimes digs into my feet and renders me immobile instantly. So I cut a thin strip of moleskin exactly the same width and length as the strap, applied it to the underside, and voila, pain-free walking.
These neon platforms from Zara don't have any strap issues, but there's the slightest gap between my heel and the back of the shoe, which always causes painful chafing and eventually, blisters, which is too bad because, um, look how darn cute they are!