Funny, I didn't see this posted at Newark Immigration, but it certainly applies.
I go through there every year or 2 on business trips, and bearing in mind I'm a middle aged (or more!) white guy, normally in a business suit, they act like i'm wearing a Burka, with an RPG strapped to my back.
While answering the normal "Why are you here" and "how long are you staying" questions i did (try to) make a humerous remark... all I got was a glare...
On the other hand, when I've passed through Dulles the last 2 years, the Immigration guys are very pleasant...