Even if you haven't seen the films in which these famous lines were used, you have surely heard of most of them. Heck, at some point, you have probably used them!
Who doesn't stand at any scenic look out, spread their arms out wide and yell, "I'm the king of the world!!!" (Titanic) Or respond to the person who just said, "you are so funny" with a, "I'm funny how? I mean, funny like I'm a clown?" (Good Fellas) Or to a "come on, tell me the truth," a, "you can't handle the truth!" (A Few Good Men).
Such genius made of on the fly! Here's the full list of the 50 Famous Movie Lines The Were Ad-Libbed.