There are things people do every day without thinking about them. Such as thinking they’re invisible in their cars and that it is safe to use public telephones.
It's OK to let the dog lick you in the face. Heavens, think about where that muzzle has been. Have you ever watched what dogs do when they get to know each other? That cute snout does not get washed regularly. There are probably more germs there than on the average toilet seat.