Some time today, somebody will tell you that this is the most miserable day of the year, and the perfect time to book a holiday, treat yourself to a special meal, or any other activity which will make you feel better and line the pockets of the company promoting it.
According to the experts – well, a former part-time psychology lecturer commissioned by a television holiday channel – today is 'Blue Monday', the day when we will be feeling at our lowest ebb as we break our new year resolutions, worry about how much we spent over Christmas, and should cheer ourselves up by spending even more money.
The term 'Blue Monday' – which may have been influenced by the 1983 New Order single of the same name – was first coined by the shortlived Sky Travel channel, which hired psychologist Cliff Arnall to come up with a scientific-looking formula to predict the most miserable day of the year.
His equation: [W+(D-d)]xTQ/MxNA – where W is weather, D is debt, d monthly salary, T time since Christmas, Q time since failure of attempt to give something up, M low motivational level and NA the need to take action – essentially concluded that the third Monday in January was the bleakest time of the year. It was later claimed that the formula had actually been drawn up by a marketing agency, and that several other psychologists had declined payment to put their name to it. Cardiff University, where Arnall had worked as a night-school lecturer, moved quickly to distance itself from the 'research'.
While Blue Monday might have no basis in science, it has to been seen as a stroke of marketing genius. Long after the Sky Travel channel's demise, the day is still regularly used to plug everything from patio heaters to recruitment agencies.
Of course, 'studies' like this are meat and drink for the public relations industry, and in the main are seen as a bit of harmless fun. But the event has come under fire from a number of mental health charities, who accuse its promoters of spreading misinformation and trivialising problems such as depression.
Dr Antonis Kousoulis, director of the Mental Health Foundation, is a fierce critic.
"Poor mental health is the greatest public health challenge facing our generation," he says.
"Trivialising symptoms of depression, anxiety and other mental health problems, under the influence of commercial industries that wish to turn mental health into an on-trend topic for profit, is unacceptable.
"Our approach should be evidence-based, involve whole communities, and prioritise prevention."
Kousoulis says it is pointless trying to identify the most depressing day of the year because it will be different for everybody.
"It is also important to distinguish between temporarily feeling down, which we all relate to from time to time, and experiencing depression or a mental health problem that can be quite disabling for our day-to-day lives."
He does acknowledge, though, that while Blue Monday doesn't exist, seasonal variations can have an effect on mental health.
"Some people might be experiencing Seasonal Affective Disorder with symptoms of depression that come and go in a seasonal pattern, and are usually more intense in the lower light months," he says.
"Bodily changes in the winter can affect our hormones and impact our sleeping and eating habits, and our mood.
"Things that are known to be good for our mental health such as exercising and spending time in green spaces are harder to do when the days are short and nights are long," he adds.
The new year can also be a time of year when people are suffering from the post Christmas hangover, having spent December eating, drinking and spending too much, and then feeling a sense of guilt afterwards.
"Perhaps the true meaning of Blue Monday is that we all have mental health and that there are steps that we can take on every day of the year to try and protect it," he says.
"We should not just be thinking about our mental health on 20th January this year, but on every day of the year.
"Depression and other mental health problems last for more than a day. And mental health problems can affect people in different ways on any day of the year."
Arnall himself has since admitted the idea of a single most depressing day was “not particularly helpful” because it became “a self-fulfilling prophecy” and argues that achieving happiness and being less materialistic should be a year-round aim.