My theory is that some people has an innate ability to be happy without spending much money. They don't travel much and don't eat expensive food ... and that's

My theory is that some people has an innate ability to be happy without spending much money. They don't travel much and don't eat expensive food ... and that's just fine for them. On the other hand, some (most?) people NEED lots of money to be happy. Their nerve systems are just low-efficiency in terms of how it is capable of converting a chunk of money into happiness.