I've grown up with three jacks, and love all dogs. I usually don't encounter many dogs that aren't comfortable with me from the get go. I've been through it all, chasing after mine, washing, them choking, the vet. I love taking care of dogs and ensuring they're in good hands. When I walk dogs or let them run in the yard, it's at least twenty minutes or until I can see they've had a solid work out.