People who want to be happy can BE happy even with 40k a year. It’s all about your needs and being grateful for what you have. The more money you make, the more your wishlist grows, it’s natural. You start making a few thousand dollars more and suddenly you feel like splurging on that amazing phone or increasing your dine out habits.
I have seen some of the most content and happiest people in my family who used to make no more than 30-40k and knew how to manage it really, really well.