-----" But the comment kept weighing heavy on my mind, as I couldn't figure out if he was complimenting Ozi, thinking he's also another HUGE GSD, or if he was insulting me. I think it's not the size comment itself, but the fact that I can't figure out if I should be happy or upset over what was said. I just don't get these people."--------
He is telling you about his own fears and insecurity far more than he is telling you anything about Ozi. He's telling you that he has a compulsive NEED to be "better" than anyone else because he feels inferior. So, he gets a big dog because that is the only basis of comparison he knows. And, if there is anyone else should happen to not know that he has the biggest dog---he will be the first to point it out so that everyone in the vicinity will know what a wonderful person he is because he has a big dog.
Actually, the whole exchange has nothing to do with you or with Ozi. The guy is just fishing for attention and verbal props for his own ego from you.
No matter WHAT you say, you are not going to change what is going on in his head, so insults and arguments are useless. Just recognize that it has nothing at all to do with you or Ozi.
Come backs that I used to use to end such self serving conversations:
"Yup, sounds like you have a really big dog alright, I'm glad you are paying his food bills and not me."
"Yeah, Ozi isn't turning out to be as big as I thought. So, I decided to work on training with him and go for smarter instead of bigger. So far, it is working out pretty well."
If all else fails, there is always the old reliable, "How high can he jump?"
"I'd better go with you Huck, civilization can be dangerous."-------Tom Sawyer(Mark Twain)