According to Freudian analysis: Female foot is an erotic organ, and the shoes are its sexual coverings. Female foot is a phallic symbol, thus thrusting her foot into a shoe symbolizes coitus. The insoles have bee seasoned with female pheromone which is an instant turn-on for men !! All men are created equal, right?
The toe prints and heel stains on the insoles have long been deposited with female feet pheromone which attracts the opposite sex and becomes the greatest turn-on for men !
Lovely and exciting. I can just smell the musky scent of nylon and worn shoe leather. Why that became inextricably linked with erections and wanting to fuck shoes remains a (pleasant) mystery.