The gross greasy slippery feeling of your toes after wearing your sneakers all day without socks on.
Pulling your feet out and having the insert of your shoe stuck to your toes.
I ran out of clean socks on Friday and had to go commando. By 10am I had such soupy toes, my sweaty feet were sliding all over inside my sneakers. it was a gross and greasy feeling and I had to toss my sneakers out.