Once you own something, you value it more than you did before. Studies consistently show that sellers demand far more than buyers will pay for the very same item. Ownership alone changes how much something seems worth.

The classic coffee-mug experiments showed this clearly. People given a mug demanded roughly twice as much to sell it as people without one were willing to pay to buy it. Same mug, same group, but possession created an attachment that inflated its value.

This is why negotiations stall and why subscriptions offer free trials: once the service is yours, losing it hurts enough to keep you paying.