Being greedy makes you sad.
All greed gets you is money, which can't buy happiness.*
Money can only buy you ephemeral moments of pleasure, which if strung together closely and consistently and in enough volume can still only provide a perfect ILLUSION of happiness, but not happiness itself.
Happiness itself takes hard work, being conscientious, and experiencing enough sadness to have a good framework of comparison.
Being happy is no walk in the park.
Now you may say, I enjoy walks in the park. They make me happy.
They only make you THINK you're happy.
But what do you know?
Then you might say, ignorance is bliss.
But how did you know to say that, if you're so ignorant?
Happiness is a logical paradox.
* Also, greed can get you THINGS.
But these things also can't be exchanged for happiness.
Only for store credit.