For All Debts Public and Private - S4-E1
Continuity mistake: Tony throws the newspaper at his son and it lands with a corner folded on the cereal bowl. From the opposite angle it is laying straight on the table.
For All Debts Public and Private - S4-E1
Continuity mistake: When Chris places the twenty dollar bill on the fridge, there's a picture of a fat kid next to it. Depending on the angle, a paper covers/not part of the photo.
For All Debts Public and Private - S4-E1
Continuity mistake: When Tony Jr. reads the newspaper, his part of the table changes completely: The napkin changes position, the orange juice comes closer to his arm, the spoon in the bowl changes positions, and a mug in front is replaced for a load of papers. The position of his thumb also swaps from being beneath a photo, to on top of it depending on the angle.
For All Debts Public and Private - S4-E1
Continuity mistake: Tony is clean-shaven at the doctor's office with Uncle Junior in the lobby and when he makes eyes with the nurse in the hall. However, steps away in the exam room, Tony now has a five o'clock shadow. (00:11:11 - 00:11:32)
Answer: It's a mafia thing. Taking food off another made man's plate in public view like that is comparable to the guy in Casino taking off his boots and putting his smelly feet up on the table.
It is not a "mafia" thing, it's basic manners and plain gross for another person to stick their fingers into a plate of your own food. Same with the feet on the gaming table scene in Casino. It's not a "mafia" thing, it's just rude and not something a person does in public.