Foot fetish?
I used to wear trainers almost all the time except for summer, when it was flip-flops, which meant the luxury of barefoot driving, which can't be a sin, because millions do it every day in India.
I stopped wearing them - trainers - after a trip through France: we were spending a few days in Payrac (near Rocamadour, Brive, Sarlat etc.) and I realised my wife had placed the 'shoes' on the ledge of an open window in the hotel bedroom. She said not a word.
Rob C