There are several very effective ways of being asked to leave the United States of America. If your intention is to stay, then on no account should you attempt any of the following.
At the Port of Entry
The first person you will meet is the one who has the most power over you. A Customs and Border Protection officer - who will be dressed rather like a police officer or security guard - will check your passport, your visa or visa waiver details and probably ask you a question or two. Customs and Border Protection people work long, dull hours staring at passports and tired visitors to the USA1 and are therefore often a bit world weary. If you don't want to wait for Deportation, you can get yourself refused entry to the country right here. The Customs and Border Protection officer has the power to deny you access to the USA and can request that you are put on the first flight our if he or she doesn't like the look of you. Your tools of choice here are attempts at humour, insults, sarcasm, wit involving terrorism or drugs, and any attempt whatsoever to look the least bit shady or dangerous.