Occam's Razor: When faced with competing hypotheses, choose the one with the fewest assumptions. Sunk Cost Fallacy: What you've invested is irrelevant to whether you should continue investing. Dunning-Kruger Effect: The less competent someone is, the more they overestimate their competence. Hanlon's Razor: Never attribute to malice what can be explained by stupidity. Grice's Razor: In conversation, say only what is true, relevant, and clear. Hitchen's Razor: What can be asserted without evidence can be dismissed without evidence. The Arena Razor: Pay more attention to people who have skin in the game.