The Paradox of Plenty

Why do we also go after something we don't have and forget about all we have?

I wanted a bigger house when I had a safe and warm home.

I wanted a bigger car when I had a vehicle that took me around when I needed it the most.

I wanted a better life when I already had a great life.

I have a lovely, hassle-free, darling stray who loves me like a pet, yet I want a pet who would love me more.

What is it with the human mind always craving for more when you already have enough?