so donald trump's most famous refrain is of course "you're fired." but get under his skin and you get something entirely different. here's jeanne moos. >> reporter: he may be a guy who portrays himself as more manley than mannerly. >> how stupid are our leaders? >> reporter: but donald trump has taken a page. >> excuse me. >> reporter: out of the etiquette books. >> excuse me. >> excuse me. >> excuse me. >> the donald has taken the childhood lesson. >> you say excues me. you used good manners. >> reporter: and trump has weaponized it. >> excuse me. i raise aid lotd a little money. >> to beat back his interviewers. >> if you want to interrupt you have to say the word excuse me. >> excuse me. excuse me. excuse me. >> reporter: some times punctuated by a finger.