Her friends are people who wear large numbers of shoes
She has a lot of friends who wear 40 and 41 shoes and sneakers, but when she compares her feet with them, in all cases her soles are bigger and her feet are the forefoot size.

"You lie about wearing a size 41 because if we both wear the same number of shoes, we would have the same size feet, but yours are bigger, so look.. You wear a 42 almost"