From Micael Lewis’s recent Obama profile in Vanity Fair:
“You’ll see I wear only gray or blue suits,” [President Obama] said. “I’m trying to pare down decisions. I don’t want to make decisions about what I’m eating or wearing. Because I have too many other decisions to make.” He mentioned research that shows the simple act of making decisions degrades one’s ability to make further decisions. It’s why shopping is so exhausting. “You need to focus your decision-making energy. You need to routinize yourself. You cant be going through the day distracted by trivia.”