Are you happy? Very happy? If you’re in your 30s or older, a new study has found that you’re less likely to answer “yes” than your parents were. The findings, published online Thursday in the journal Social Psychological and Personality Science, come on the heels of another recent report that found that death rates of middle-aged white Americans have been rising, largely due to suicide and substance abuse. Shigehiro Oishi, a researcher at the University of Virginia, has documented a growing dissatisfaction with the widening gap between the wealthy and everyone else.