I've been a visa requiring foreigner for about a third of my life, and I have found that apart from being nice, humble and unassuming the best is to dress conservatively, be clean and just basically look like you are too conservative to break any rules. Also make sure you carry the right papers, know all the questions and have answers to them, and have enough sleep beforehand.

That's a pretty lame excuse for having someone repeatedly treated like shit.

I think you are right, even though you got downvoted.

I'm not white. In fact I look like I could be the younger, nerdier brother of Mohamed Atta. I got off my green card and became a US citizen only in 2009 (After I was sure McCain wouldn't become President, and after I was certain they couldn't draft me :-)

My papers have always been in order, and I've never had a problem with any customs or border guards.