Thank you all for your responses!! I feel much better now. I always supervise Brody in the yard, and I've seen him crouch when our neighbor approaches. It looks to me like he's kind of cowering, but my husband thinks it's more of a play bow. Either way, as long as I can be confident it's not aggression it's all fine with me (I never thought it was aggression, but I still worry anyway). I definately think the problem is not with Brody, but with our neighbor! Brody has been well-trained and well socialized, which is more than I can say for people who screw with someone else's dog over their fence! DH is going to talk to him (I guess I, like Brody, am too submissive to approach the issue) and hopefully that will be the end of it. We'll all be happier once the privacy fence is built. Thanks again for your responses and support!