you'd think a grown man would have at least some common sense...
IMO, Goku's reaction was totally normal... however... when my dog displays appauling behavior I think to myself, "what if that were a kid?" - this time it wasn't, but next time he's grabbed unexpectedly, it could be a kid. It's atonishing how many kids aren't taught how to approach a dog.
I don't blame your dog for one second for the nip - but a simple and even provoked nip, can have drastic consequences.
I think it's a blessing in disguise - no one got hurt - and you learned something important about your dog - now you can watch for it, and prevent it.