If you want to get into the spirit of the occasion, give your friend a big smile and a high-five as you cross paths, right before you sneak up on him with knife in hand. Works even better when you conspire with your friend’s other friends and take turns stabbing. An individual backstabber is likely to be perceived as selfish, not to mention treacherous, but a group of backstabbers seems purposeful and, well, group-minded.
And keep in mind that backstabbing is only fun when the victim seems genuinely surprised by the first knife thrust. That’s why Julius Caesar is such a great role for certain actors. It calls for magnanimity as well as arrogance. And gravitas, of course. Louis Calhern is well-cast in the old film version of Shakespeare’s Julius Caesar, the one with Brando as Antony. Rex Harrison is a grand Caesar in the movie Cleopatra, but he sometimes seems on the verge of belting out “Talk to the Animals.” The best Caesar on film is Ciaran Hinds in the HBO series Rome. The man has gravitas and is too sure of himself to heed warnings. He looks convincingly shocked that his friend and protege Brutus is among the conspirators. And the writers were smart enough to leave out the unnecessary et tu.