Reasons dogs lick: affection, attention-seeking, maternal instinct, taste. Usually harmless, but can be trained to lick less if annoying.
Dogs lick people to show affection and learned it from their mothers. It's a natural behavior and not a serious problem.
Attention-seeking dogs seek any form of attention, even negative reactions. Instinct: Licking may be passed down from wolves, who regurgitate food for their young.
Dogs licking humans for taste, but obsessive licking can be a disorder. Vet and behaviorist help, medication may be used temporarily.
Dog licking generally harmless, but mouths contain bacteria. Unlikely to cause harm unless enters open wound. Can be seen as gross.
Deny attention when dog licks. Reward when it stops. Attach word to gentle kisses. Consider hiring a trainer.