One trainer advised to idiot-proof your pup (by owner). Touch the pup unexpectedly, gently pull on tail and ears and feed a treat immediately. This paid of big time in the past when a nursery employee saw my Pit mix male (3 years old), walked over, knelt, squealed (Oh, you're so cuuuuuute!) and hugged him frontally without giving him the chance to meet. The dog knew what idiots do and remained neutral/friendly, being the wisest of all of us.