Dogs can be real characters! My mutt boy is very vocal during playtime, growling and barking, and sounds like a grizzly bear. As long as you can differentiate between playtime and serious, you're good. When my boy is serious, he sounds like a much bigger dog than he really is. Example, I got up this morning to get the kids up for school, and didn't think to turn on any lights. He didn't hear or see me til I set my phone and cigarettes down on the table next to the couch. I turned around him creeping up out of the kitchen, posture low, tail down, ears flat and eyes fixed on me, growling real low and deep. I turned the light on and said his name "Rolls!", and he stopped growling and his whole posture changed, lifted his head, laid his ears back and started wagging his tail. I patted his head and told him he was a good boy. Now, some people may not approve of my way of handling my dog's reaction, but I know dogs don't see as well in the dark as they do in the light, and I also know that I have a neighbor/tennant (I'm the apartment manager) who is very suspicious and dangerous (unfortunately, legal proceedings are holding me up from making him leave the property). So, I gladly accept my dog being protective of the family and house. I don't "sick" him on anybody, but I do reinforce the desired behavior by praising him when he does his job. He's a mix of unknown origin, but his paperwork from shelter & previous owner say lab mix, my vet labeled him a rottie mix, but he looks to be lab/shephard mix at best guess. Anyway, I'm rambling... The point I'm making here, is I'm glad you get a kick out of playing with your pup, and hope you know your pup well enough to tell the difference between play and protectiveness or possible aggression. It can make a huge difference in your life and your pup's in the long run.