The study, led by Sandra C. Matz at the University of Cambridge, and published in the journal Psychological Science, used data from more than 76,000 transactions, and found that purchases of material goods and services only made people happy when they were in line with people's personalities. The researches even found the link between happiness and personality-fitting purchases to be stronger than the link between happiness and total spending and income. So it's not about how much you spend or how much you make, it's about spending what you have the right way. And the right way is to make purchases as a form of authentic self-expression. Buying things to fit in or go with the flow won't make you feel content in the long run.
Money Buys Happiness When Spending Fits Our Personality [Psychological Science via Greater Good Science Center]