When you completely quit a habit, typically smoking right away. It is very painful and puts you in a very irritable mood. It is very different than giving up gradually. When giving up gradually, you smoke littler and littler each day.
Guy #3:Shut up!!! Both of you!!!
Guy #1: Why is Guy 3 being such a bitch?
Guy #2: He started cold turkey today. He has been smoking for the past five years.
Guy #1: Wow that must really suck.