i used to work for macy's when i was an intern learning the business. in the customer complaints i had to deal with fuming, hot headed individuals who, at times acted like they were out for revenge or blood. and i carried over the frusteration at home, arguing and shouting at my parents. i soon left that job and vowed never to work in retail again
I used to work at a gun store and have had several loaded weapons pointed at me (mostly due to careless owners unfortunately) and have been threatened by customers to the point I had to make ready with my own firearm.
When I worked residential construction, change requests always seemed to come well after a bunch of work had already been done. Frustrating, especially when the client does not want to pay for the change.