You shouldn't tell people to back off.
Don is at a bar when another patron gets uncomfortably close to him.
Don wants to clear up some of his personal space.
Don asks the other patron to please give him some room to drink his drink.
Don yells at the patron and tells him to back off or else.
The other patron apologizes and takes a step back.
The other patron gets belligerent and throws a punch at Don.