You need lots of stuff
They say you should cut down the number of things you own to 51, to be happy (there are websites on how to reach that number).
That’s not true.
What you must do is you must acquire a great number of things, thousands upon thousands, and you need to arrange them all on shelves and set up proper lighting to see them and show them to others. And you should wait for 51 people to tell you: ‘Ah, your collection is wonderful. I wish I had one just like it!’, and then you should give all your stuff away, divide it equally between the 51 individuals (there are apps that’ll help), and when you’re down to zero, ask each of the 51 to give you back an object of their choosing, and then drop me a line to let me know if it worked, the happiness thing.