I had one lady walk into Petco and talk to me about getting rid of her young lab pup (very tiny, probably 6-8 weeks) because of that same reason. I tried to talk some sense into her but she wouldn't listen to me, she had already decided.

Nebo was a holy terror puppy. I could have gotten rid of him as a pup for a dozen different reasons...but I didn't give up on him and now I have a wonderful dog. People just don't seem to be able to take the time to teach their dogs and let them grow up.