Try and picture the inside of your own head. Does it have colour? If so, what colour ? What is it all made of? Not the brain itself, you understand, but all the stuff inside the brain. It is just out of your reach, no matter where you grasp, and you are like a drunk reaching vainly for a lampost to prop himself up. And all those half formed ideas that you barely understood loll out of the ooze. You read the page and it means nothing. It is all anger and fear. Headache stuff. There is no light in there - which is why you yearn for holidays in the sun.
But try describing any of this to a friend. They will say, Ok, mate. They will not want to know and they will tell you that the inside of their head looks like a Disney cartoon, with animals anthropomorphized and gloriously congenial to one another. There is no hint at the murder and savagery of life here - females with big brown eyes and long eyelashes, and all rendered in solid blocks of colour, definite and easily understandable.
Sometimes, though, it clears. And you feel like a Saturday night party.