dog aggressiveness

Question
Hello, I have a 2yr male German Shepherd/Ridgeback mix named Toby. Since
he was little he has always been a toy thief at dog parks. He did it for
attention and of course it was never pleasant; most dog-owners were
completely annoyed. Through time as he got older his grasp on his
commands became much better. Now he doesn't steal toys or if he does
"Drop It Now" works just fine and he drops and comes. Lately though I've
noticed he has a new game that causes aggressive behavior in other dogs,
which he instigates. This new behavior involves getting a large branch or stick
from the woods around the park and running at other dogs with it in his
mouth. When the other dog sees the stick and tries to play with it with my
dog, he attacks them. Most of the time it is just posturing and it ends without
any blood, but it seems to be more frequent as he gets older. I discipline him
harshly for it, I try to leash him asap or leave the park and go home. He gets
yelled at with a loud "NO" and a firm jerk on his collar. He appears very guilty
and sorry, he'll then go and lie down out of sight at home. The thing is he'll
do the same thing again and again? What am I doing wrong? Is this just a
personality flaw? He was well socialized his whole life, neutered and has many
dog friends that he gets along with just fine...this happens on random
occassions, recently with a pit bull-which wasn't a good situation. What can I
do to stop the behavior, and is it OK to bring him to an off-leash Dog Ranch
when I go on vacation this holiday season? Some people have said that dogs
behave better when their owners aren't are around?

Answer
Hi Lauren;
I don't think you can say they behave better for others than their owners.
It depends on whether or not the owners discipline them and hw they do it.
I would suggest you take your dog through a group obedience class at Petsmart, Petco, or Man's Best Friend.
Tell your trainer of this behavior that you particuarly want to stop
Charlotte