everything that rbcp is very very important. personally, i think the most important thing of all of course is to not make a person feel threatened. if you dont let a person feel threatened in a call, then it never gets to a point where it gets out of hand, and thats a general good rule of thumb. its better to make a call where a person is confused, says 'what the hell?' be it out loud, or in their head, and nothing else is said until they speak, rather than saying the wrong thing that puts a person into a panic. if you pay attention to rbcp's way of making calls, after a while you will see that he has a great sense of this. some of the best prank calls are ones where the person is truly and solely confused, but stays on the line to see what happens next. with any call, just like with any conversation with anybody, its give and take. that is i think what makes a great prank great, the feeling of suspense in both the execution as well as the reaction.