It's rude to use your sink to wash your feet.
Jon has guests over and just got in from chasing his dog around the yard while barefoot.
Jon wants to clean off his feet.
Jon goes to the bathroom, closes the door, and washes his feet off in the tub in private.
Jon puts lifts one foot at a time into the kitchen sink to wash his feet in front of his guests.
Jon's guests enjoy their evening and Jon and his dog.
The guests are appalled by Jon's choice to use the kitchen sink and second guess eating any food prepared there.