Agree with the eating breakfast off the table thing. DH agrees with me, fortunately, probably after the 10 yrs we spent in the tropics, where huge ants are very quick to make a direct line attack on drops of jam/honey on your tablecloth.
Agree with the smacking thing, too, though often those doing it don't realise how shocked others are: it's just that no one dares intervene, but if you talk to other mothers they'll often say they're upset by someone's smacking habit.
Spitting in the streets.
Dumping rubbish.
Speaking incredibly loudly and obscenely (because we are Mediterranean, dontcha know,); the other day there was a guy on his mobile under my window shouting at his mate, "I'm opening the bids on your mother's pussy".
Thinking homophobic insults (PD, enculé, etc.) are acceptable to use at every possible opportunity.
Re sweets: DS's teacher gives them sweets at school, and the neighbour routinely buys her DD sweets while getting the lunchtime baguette, so her DD scoffs them on the way home for lunch. Yesterday, the DD offered DS one, and the mother said, "ooh, maybe that's not a very good idea, it might spoil his appetite." And not her DD's??