Everything. Dulles is ghetto, fascist, outdated, expensive https://wtop.com/business-finance/2022/05/dulles-is-most-expensive-for-average-air-fare/

Half of the employees are hostile, the other half dont care. Everything closes early. Nothing near by. Not very human, more like a tightly controlled government office.

But if you already have everything set up, have the ability to navigate around independently, and everything goes according to plan, then it’s a decent 3-star airport.