We all know there's nothing more depressing and soul-destroying than cleaning the family home again and again. Playmobil and toy clutter back in boxes. Tick. Washing up - again. Tick. Sorting socks - again. Tick. Cleaning gungy high chair crevices. Tick.
But now it's official - scientists claim our obsession with cleaning could be linked to rising rates of depression.
They believe that eliminating bacteria and viruses has actually made our immune systems weaker, and this in turn has affected the functioning of our brains.
Scientists have long blamed our overly sterile environments for increases in asthma and allergies. They say some bacteria are necessary for bolstering our immune systems, and without them our bodies over-react to dust and pollen, resulting in an allergy.
But now researchers believe that this over reaction may also impair the brain's ability to produce certain chemicals that make us happy – such as serotonin, the 'happy hormone' – and this leads to depression.
They point out that rates of depression are far higher in the Western world compared to poorer nations, because people's immune systems are less trained to cope with bacteria.
Around one in 10 Britons suffers from depression compared to just one in 100 in Nigeria, for example.
Dr Andrew Miller, one of the scientists in Atlanta, Georgia, said: 'We believe the immune system is causing depression.
'As people develop and grow up, their immune system develops. If they are exposed to more bacteria and parasites, they are able to better control the inflammation.
'Nowadays people's environment is much cleaner and hygienic so our immune system never really learns how to deal with infectious agents. We are overactive because our immune system has not been trained.'
The researchers, whose study was published in the journal Molecular Pyschiatry, are now testing whether anti-inflammatory drugs could be used to treat depression.
So next time you're faced with a chaotic kitchen, just think 'this is not depressing, this chaos good for me and my children' and have a cup of tea and a biccie instead of cleaning.