Every one of joker seems to have a “defect” and for Sal it’s his flat feet. Lucky for him, this is only noticeable in the rare occasion he has to take off his shoes.
Consequently, it’s not so much about their appearance as it’s the feats that this flatness affords Sal.
For it is my conjecture that it this hidden quality that’s to blame not only for his unstable “down to earthiness” but also explains the ease with which he executes the highly unstable double-dutch.
Impractical Jokers S5E20 The Chairman
We are introduced to Sal’s peculiar flat feet in the first challenge of this episode where the jokers have to do as they’re told while barefoot in a department store.
Impractical Jokers S6E19 Flatfoot the Pirate
Sal goes bare feet in this episode’s punishment at a children’s event where he’s playing the well fitting role of Flatfoot the Pirate.