A new survey has revealed the average British worker will spend around four weeks a year daydreaming.
And, worryingly, this is costing at least £1,000 each in lost productivity.
But the apparently wasteful habit could be the secret to success, health and well-being, as the Mirror reports.
Neuroscientists say it can form new brain pathways and develop our ability to solve complex problems.
Online gaming company, GalaSpins.com questioned 2015 UK adults aged 18-65.
It found 61 per cent of people daydream for around 30 minutes a day, with those aged 18-24 the worst culprits, and men more likely than women to let their minds wander.
The office is the favourite place to daydream for most (61 per cent).
This is followed by bed (34 per cent) and the shower (33 per cent).
Two-thirds (67 per cent) fantasise about desired situations or scenarios (usually featuring family or friends).
About 60 per cent take a walk down memory lane.
Linguistic expert Dominic Knight said: “Remembering the past and projections into the future affect the structure of the brain and facilitate in forming new neural pathways.
"Einstein and Steve Jobs were daydreamers.”