From Bankrate.com http://www.bankrate.com/finance/s...spx#slide=
Very useful financial education; e.g., Can Money buy happiness?
"Income increases also improved subjects' "emotional well-being" -- the quality of their day-to-day existences -- up until they reached the $75,000 mark. Earnings above $75,000 did nothing to improve subjects' daily attitudes. As income dropped below $75,000, test subjects also reported more stress and less happiness."
Comment: I am not sure $75,000 is the threshold; it is "to each his own." But poverty definitely ruins happiness and marriage.