My friend's dog is exactly like this. Every object is something he wants you to throw for him, and every person or person-shaped object is someone who has, in his mind, NO REASON not to throw it for him.
It takes a coordinated effort of at least two people telling him no to get him to leave you alone and stop dropping his slobbery kong on your lap.
One of Pavlov's dogs says to the other "you know, that Pavlov fella seems to have a preconditioned response -- every time the bell rings, he brings us food!"