If you have money, the unexpected is an inconvenience. Yeah, it sucks when the car breaks down, or the cat needs to go to the vet, but you can afford it.
It’s hard to be happy when you can’t afford the basic necessities of life or know that one tiny problem will destroy your precariously built stability.
Rich people can throw money at problems and make them go away. Middle-class folks can control their work schedules, take time off for illness, and hold out for the perfect job opportunity.