I think it starts when we're, what? Four? And in a sandpit with our new toys determined to show everyone around us that our stuff is way cooler. And if our stuff just visibly isn't cooler - at least, we don't think it is - then we suffer pangs of anxiety, insecurity and the certainty that life just means nothing.
And years on... well, not much has changed, has it? We constantly compare ourselves to other people. Mrs Perfect Mother's baby never cries. Mr Debut Novelist got given a seven-figure advance on his first book. Those reviews are better, my book just isn't up to scratch, she's prettier, my toes are wonkier (and they are, too. I swear my littlest toes are misshapen.)
I've found it's pretty much unavoidable. I'm always going to compare myself to other people. But I've learned not to find myself so lacking. I've learned to judge myself by my own standards and not worry too much about the rest.
So how do you cope? What do you do when you start comparing myself to someone else?