Philip Seymour Hoffman
Actor for whom the rule was that there is no such thing as a bad Philip Seymour Hoffman movie - later, in the light of the evidence of Red Dragon and Prac Crit Porridge, adjusted to be that there are occasionally bad Philip Seymour Hoffman movies, but he is never bad in them (much like the Paul Bettany and Richard E Grant rules).
Hoffman had a dark inverse to this rule in the form of Jennifer Aniston, for whom the rule was that there was no such thing as a good Jennifer Aniston movie (aside from her voiceover work in The Iron Giant). This meant that Along Came Polly, in which both Hoffman and Aniston feature, posed something of a rule-tester. Mark ruled that Along Came Polly remained a bad Jennifer Aniston movie, but one that was elevated by Hoffman's presence - putting it at the top end of her oeuvre but the bottom of his.