Young people mispredict happiness levels in old age, believing—wrongly—that happiness declines with age.
Young male binge drinkers are particularly prone to thinking that happiness declines with age.
References:
Mispredicting Happiness Across the Adult Lifespan: Implications for the Risky Health Behaviour of Young People. Journal of Happiness Studies, 2009.
Experienced happiness is largely set by personality, it will temporarily respond to changing circumstances. The Lancet, 2010. http://goo.gl/ot3Kx
Image source: OpenClipArt.org, public domain.
Image source: OpenClipArt.org, public domain.