" We humans have known since time immemorial something that science is only now discovering: our gut feeling is responsible in no small measure for how we feel. We are “scared shitless” or we can be “shitting ourselves” with fear. If we don’t manage to complete a job, we can’t get our “ass in gear.” We “swallow” our disappointment and need time to “digest” a defeat. A nasty comment leaves a “bad taste in our mouth.” When we fall in love, we get “butterflies in our stomach.” Our self is created in our head and our gut—no longer just in language, but increasingly also in the lab. "

― Giulia Enders , Gut: The Inside Story of Our Body’s Most Underrated Organ