A recent report shows that London Taxi drivers are Britain's grumpiest workers, according to a survey on Monday, while secretaries are the happiest.
The gloomy prospect of ferrying around strangers every day makes taxi-drivers laugh less than any other profession, according to the survey of 4 000 workers.
Drivers cited traffic jams, the rising cost of petrol, drunken passengers and frisky couples as reasons not to be cheerful.
Fitness instructors could lighten up too, with just 0.9% of them saying they enjoy a giggle in the gym.
Those in recruitment could also do with a good dose of humour, the survey said, as just 3.8% laughed regularly during the working day.
By contrast, 53.5% of secretaries said they laughed on a regular basis during a working day, with a quarter of those surveyed confessing that most of their amusement comes from watching the stressful lives of their disgruntled bosses.
Other workers scoring high on the laughter scale were, perhaps surprisingly, accountants - many of whom said they regularly played pranks or wound up their workmates to alleviate the daily grind - and teachers.
The results of the survey, conducted for comedy TV channel G.O.L.D. also revealed a correlation between laughter at work and days off taken sick.
The more we laugh, it seems, the less we skive.