Once you have done a crime you need to do another to cover it up... and I think the theatrical intensity in that... the vividness of the relationship between Macbeth and the audience... pulls you through those experiences... in a way which, in a half decent production... is extraordinarily exciting and involving... and when Malcolm comes on at the end... and dismisses the chap he'd just spend the evening with... as a 'dead butcher' and his wife as 'a fiend-like queen'... you say, uh, uh, you don't know the half.