What the data actually shows
In a notable set of studies, Iris Mauss and colleagues (2011) found that people who place a very high value on happiness can end up less happy, especially in otherwise positive circumstances — in part because valuing happiness leads people to monitor their feelings and feel disappointed when reality falls short of a high standard. They titled the work, fittingly, 'Can Seeking Happiness Make People Unhappy?'
Research distinguishing happiness from meaning (Baumeister, Vohs, Aaker & Garbinsky, 2013) found the two overlap but diverge in important ways: a meaningful life involves giving to others, connecting past-present-future, and sometimes stress and effort, whereas a purely 'happy' life skews toward having needs met and feeling good now. People can have a highly meaningful life that isn't always pleasant — and vice versa.
Across wellbeing research, the most reliable contributors — close relationships, engagement, contribution, a sense of meaning — are things you pursue for their own sake, with positive feeling following, rather than feelings you target directly.
Why this feels different from how it actually is
The culture frames happiness as the explicit goal of life and sells it as something you can acquire — through purchases, achievements, or self-optimisation. That framing makes 'just be happy' feel like a reasonable target, when the evidence suggests targeting it directly is part of the problem.
Constant access to images of other people's apparent happiness raises the bar and intensifies the monitoring ('am I as happy as them?'), which is exactly the mechanism shown to reduce happiness in people who prize it most.
What the research says to do about it
The research points toward aiming at the sources rather than the feeling: investing in relationships, doing absorbing or meaningful activity, acting on your values, and contributing to others — and letting positive emotion be the byproduct rather than the target.
Reducing the monitoring helps. Findings on valuing happiness suggest that loosening the constant self-check ('am I happy enough?') removes the disappointment loop that undermines the very state you want.
Pursuing meaning and engagement is associated with durable wellbeing even when day-to-day pleasantness fluctuates, which makes them more robust aims than happiness defined as feeling good right now.
What the research says does not help
Setting happiness itself as a constant target and measuring your mood against it tends to lower wellbeing — the monitoring and the high standard are the documented culprits.
Treating any dip in mood as a failure to be fixed adds a second layer of distress on top of normal emotional variation; happiness research consistently finds fluctuation is normal, not a malfunction.
Buying experiences or products specifically to 'become happy' often disappoints because of hedonic adaptation and because the direct pursuit raises expectations the purchase can't meet.
Real numbers in context
In Mauss and colleagues' experiments, participants induced to value happiness more highly reported lower happiness in positive situations than those who weren't — a counterintuitive reversal that has been replicated in related work on the 'pursuit of happiness' paradox.
In the meaning-versus-happiness research, measures of meaning and of happiness were correlated but separable, and several factors (helping others, higher stress, deeper engagement with difficulty) raised meaning while not raising — or even lowering — momentary happiness. The 'good life' the data describes is not the same as a continuously pleasant one.