Numbers don't lie, but people do—sometimes without even knowing it. In sport, objective measurement (reaction time, jump height, oxygen consumption) gives us the "what." Subjective measurement (confidence levels, perceived effort, coach instinct) gives us the "why." The problem arises when we treat one as truth and the other as noise. That's where the psychology of financial decision making becomes a game-changer. It teaches us that whether you're reading a balance sheet or a heart rate monitor, the same cognitive biases apply: status quo bias makes you stick with familiar metrics, hindsight bias rewrites what you thought you saw, and endowment effect makes you overvalue the data you already collected.