Jean-Paul Sartre said this quote

“ It would be much better if I could only stop thinking. Thoughts are the dullest things. Duller than flesh. They stretch out and there's no end to them and they leave a funny taste in the mouth. Then there are words, inside the thoughts, unfinished words, a sketchy sentence which constantly returns...It goes, it goes ... and there's no end to it. It's worse than the rest because I feel responsible and have complicity in it. For example, this sort of painful rumination: I exist, I am the one who keeps it up. I. ”