Why do we value our old mug, unused concert ticket, or even a car with a new seat cover far more than anyone else would? This is the endowment effect, a cognitive bias that makes us overvalue things simply because we own them. From classic psychology experiments to everyday resale dilemmas, the endowment effect shapes how we perceive worth, often leading us to make irrational choices.

We often think we’re being rational, but our brains love shortcuts. The availability heuristic is one of them, our tendency to judge something as more likely just because we remember it easily. A news report on a robbery can make us feel unsafe for weeks. A recent stock surge can tempt us to invest. But easy-to-recall doesn’t mean true or likely. Our minds favour what’s recent, not what’s accurate