The study, which surveyed more than 2,000 UK employees, found that one in six British workers over 35 said they were unhappy, which is more than double the figure for those under 35. Put in a different way, only 8% of 18-to-34-year-olds consider themselves unhappy at work. Comparatively, 16% of 35-to-49-year-olds and 17% of people over 55 feel the same way. People over 55 were the most likely to feel under-appreciated, with nearly a third saying this was the case.