I wish people would come with Warning! labels. Some people, in fact, do display the obvious signs but for most learning to read that warning label is a form of art.
Once in a while I am caught completely off-guard. Appearances can be misleading and there are people out there who will simply stab you in the back, even if you have not done anything to provoke it. Sometimes, it’s simply a matter of trying to get ahead or justifying their actions. Sadly, I almost never see these signs in people. So I wish people would come with a Warning! label.