In my opinion, people try to achieve happiness with money. These days, the money look like the main goal of everyone. When you ask someone which are the things that they look for a job, the first is always how much money they will earn.
It is known that people need money to survive, but this mustn't be the only reason to get up every single day. If you have a high incomes, you afford better things than people who have a low salary could not. But even if we have more money than we can waste, we couldn't skip from traffic or heavy rain above your head.
But when you see all the good things behind, you feel remarry with money. You observe the good things that it give you but you don't argue with it about the things that you do not have.
To conclude, the relationship between income and the happiness of an individual might not be together. The happiness of an individual is more about ourselves than output we receive from out, like feeling light and healthy.