If your flats or heels are causing you trouble when you try to get them on(barefoot) or are causing blisters then spray your feet with a deodorant or perfume. Then simply slip your shoes on!!! This worked a treat for me as every time I was going out in my heels I'd always have to wiggle my feet in to my shoes for a few minutes. Then one day I tried spraying the inside of my shoe with deodorant and my shoes slipped on to my feet with ease!!!