Screenwriters put this stuff on paper and it's up to highly-paid actors to put it across in a way that makes it powerful, or hilarious, or at least memorable. One actor's inflections of a certain line of dialog, no matter how good the actor or the writing, might be flat and unpersuasive, while just the right person can take it into the stratosphere. Example: "What a dump!" as spoken by Bette Davis in BEYOND THE FOREST, or her equally wonderful "Fasten your seat belts....it's going to be a bumpy night." from ALL ABOUT EVE. Or any of a dozen lines spoken by Bogart in CASABLANCA. Or Joe E. Brown's "Well...nobody's perfect" in SOME LIKE IT HOT. But how about a few of the less famous examples of actors putting their spin on dialog so that it just sticks with you forever, even if the movie itself fades from memory. My candidates to get things started (can you recall the scenes?): Nigel Davenport's delivery of the line, "It had occurred to me" in A MAN FOR ALL SEASONS. William Holden's scalding comeback to Jack Hawkins in BRIDGE ON THE RIVER KWAI: "They don't know it, but I do." Jonathan Winter's delivery of the line, "This is a little girl's bike..." from IT'S A MAD, MAD, MAD, MAD WORLD. Please feel free to add some more!