this is insane. i genuinely don't understand why ambitious people aren't shown this lecture before their careers start consuming their entire lives. clayton christensen spent his career studying why successful companies collapse. in his final class, he asked students to apply the theory to themselves: if you keep allocating your time the same way, what life are you actually building? he had already seen the answer in his own harvard mba class. everyone looked successful at the fifth reunion; by the 10th, 15th, 20th, and 25th, many were unhappy, divorced, and living far from their children. work shows you the score immediately. close a sale, ship a product, finish a presentation, earn a promotion, get paid. an hour with your child may produce nothing you can measure today; it may take 20 years to understand what that hour built. so the next free hour goes back to work, one rational decision at a time. this is how people build lives they never planned: through hundreds of right decisions that lead in the wrong direction, day after day. money, titles, and headcount are easy to count. christensen believed a life should be measured by the people who became better because you were there. he died in 2020. one question remains: if someone saw only where your time, energy, and attention went this year, what would they think actually mattered to you? the full 19-minute lecture is in the video below.