Over-focusing on "my" leads to unhappiness

"You are looking at a beautiful porcelain vase in a shop window when a clumsy salesman knocks it over. “What a shame! Such a lovely vase!” you sigh, and continue calmly on your way. On the other hand, if you had just bought that vase and had placed it proudly on the mantle, only to see it fall and smash to smithereens, you would cry out in horror, “My vase is broken!” and be deeply affected by the accident. The sole difference is the label “my” that you had stuck to the vase."

From Happiness: A Guide to Developing Life’s Most Important Skill by Matthieu Ricard