Another thing I worry about with my dog is small children wanting to pet him when they see him...a lot of times without parent permission.
One time my cur snipped at a little girl that suddenly pawed him on his face, all love of course, but he doesn't like that and he snarled and snipped...I saw it all happen and tried to intervene but children are quick! I was however immediately able to immediately put my dog in his place. I immediately apologized to the mother of the child, who also had been slow to react and had been unable to control her child. Gratefully she was understanding and we were able to teach both the child and the dog a lesson The little girl learned not to run up to random dogs without asking first, and the cur, well he learned that he is absolutely NOT supposed to snip at children...they ended up being friends
Knowing your dogs temperament is important. You should know if your dog doesn't like children, or other dogs, or doesn't like being touched a certain way. My dog doesn't like being patted on the top of the head by strange men and will get kinda rowdy, so when people ask to pet him I warn them of such.