Believe it!
I was 16-17 (7 years ago), I didn't require a visa (as far as I remember). I had previously traveled to european countries in which I needed no passport at all (just your ID card, and it was not required at the airport, you were just required to have it while in the coutry).
For me it was very shocking the entrance to the USA having experienced it in Ireland, France and England.
I was first interrogated about my luggage. Then passed the Barajas airport security. While I was in the plane they gave me a green card (a green form) in which such questions were made (are you going to kill the president, have you killed an american citizen in your country and other such funny questions). I couldn't believe it! I was advised that the policemen in the States was very tough, so I decided to fill it in in a serious way (but I was laughing at it).
When I arrived to the New York airport I had to wait a lane two hours, to be treated as a third world inmigrant who was going there to work. A policeman yelled at me (first time in my whole life a policeman did that and the first time I couldn't even explain anything to him, I just did as ordered, but I let myself whisper a "vete a la mierda" hehe).
While in the country I was twice more treated in a rude way by policemen. This was very shocking for me, here the policemen are generally very polite and correct, but I guess the policemen in the USA have a worse and more dangerous job, so I can undestand why they are as they are.
That didn't ruin my studies trip of course
It was just an anecdote. When we were back here we laugh at all these things...see, what crazy the american policemen are :p Are they really that way with american citizens? Or was it just with forgeiners?
Fernando