I have a 6 month old Puppy and he LOVES playing fetch. If he finds a ball he will drop it at our feet and happily play non-stop until we tire/we think he's getting too tired! He never has any issues with guarding and is always happy to drop the ball to play again.
Sometimes he gets really excited about us throwing the ball in an anticipation and almost verge on frustration that we are not throwing the ball fast enough! We don't reward that behaviour and will stop playing if he does that.
It crossed my mind, can his love for fetch become too obsessive or become a problem? Does this ever happen?? I've heard of dogs being very possessive of balls but he doesn't have that. He just wants the game.
He loves fetch so much we use it as the reward during training rather than treats. He'll do anything for it! 