Once you arrive at the US, you have to get past passport control and customs. That's what most people worry about, but it's less unpleasant than getting the visa. The problem is only that the personnel act overworked, surly and suspicious - very unwelcoming.
Far worse is the process of getting a visa, because this requires visiting the American embassy. The place is built like a prison, and that's pretty much the feeling you have when you are there: the personnel is behind thick glass windows with over-pressure against poison gas, talking to you through a crappy speaker. Even though you may "have an appointment" you often spend hours waiting. Sure, your appoint may begin on time, but then you wait again, then go to some other window, then wait some more, then go pay at the cashier, who may be on her lunch break...
And you aren't allowed to take anything in with you. Just your wallet and any paperwork you may have. No bags, not a phone, not a Kindle. I've learned that they let me take in a physical paperback, a pad of paper and a pencil - that's as far as you can stretch the rules.
The process of checking people to let them inside is slow, and the only place to wait is outside - if it's stormy, windy and raining, be sure to dress warmly. But not too warmly - you can't have a backpack or anything, because the embassy has no provision for your belongings. They don't want them on the premises, so you have to find someplace else to leave your stuff. The obvious spot is the train station, which is about a mile's walk away (there's no parking at the embassy, they're far too paranoid for that). This is really great for people who are visiting for the first time, because they naturally assume there will be lockers or some other provision for their belongings; they face a 40-minute walk to deposit their stuff elsewhere, missing their appointment. It is also great for families with babies or small children, since you can't bring in your kiddy bag to take care of them.
The whole setup is a truly unbelievable PITA - you have to see it to believe it.