There are few more disgusting things than people who eat and then lick their fingers afterwards.
The bosses at KFC seem to agree, that's why they've changed the slogan from Finger Lickin' Good to So Good. The marketers of Oreos need to get the same message. Their adverts encourage children to lick their biscuits. Gross.
The only things suitable to be licked in public are lollies and ice creams.