Your title asks who has had no problems and then you ask what problems have you had.
I've had my dog bite the gardening bc he snuck up on me and my dog training. He had a leaf blower in his hand and my dog must of thought he was a threat and bit him on the calf.
Nothing came out of it, his mother called to make sure he was up on all his shots and was clear of rabies and that was it.
The only other scare I've had is a torn ACL. He was walking and running funny for a couple days so I limited his activities and he was still acting funny. Took him to get X-rays and what not, but came back clear and he started acting normal a few days later.
So for the most past, things have been pretty good.