And more importantly, why haven’t they fixed this problem yet? It’s really dangerous. I meant to give someone $2 today, but since the bills were new and stuck to each other I accidently gave them $3. OK, it wasn’t that terrible but imagine if they had been 100’s!
Do other countries have this problem with their currency? Is this the Treasury Department’s idea of a practical joke?
I have never noticed new currency being sticky. Perhaps you should wash your hands.
Then you’ve never had a stack of new bills. Those muthas stick together like clever analogies to the Straight Dope.
I don’t know. It may have something to do with the printing process which is intaglio. The design is actually embedded into the paper. When I get one of those brand new bills the first thing I do is crumple it up. Then it’s no longer “sticky.” There was a bank branch in Jefferson Plaza in Alexandria, VA that must have been a main outlet of the Federal Reserve for new currency. It seemed like all of the bills they handed out were new.
Why are new (US) bills so sticky?
So they don’t slip too easily from your fingers 
They also tend to feel almost dusty, but not quite. That texture certainly must have some effect on their stickiness. And you left out the part where they smell terrible and make harsh, unpleasant sounds when counted.
I like the smell of fresh money.
Also tennis balls.
Are you familiar with the smell of several thousand of them left in a safe for hours? It’s this vaguely clay, kinda dirt smell that I will never learn to love.
Unfortunately, they don’t stick to your fingers so much as they stick to each other. 
Yeah, you peel off a one and another comes with it. And have you noticed that if you break a five these days it lasts hardly any time at all.
Why would you leave several thousand tennis balls in a safe?
Duh. For safe-keeping, silly. 
Any packed paper is difficult to separate because air has been compressed out of the stack and a static charge holds the sheets together. Shuffle a new deck of cards and it will sit higher than a new unshuffled deck because there is more air between the cards and they are easier to deal because the static charge has been reduced.
The trick is force more air between the bills. Something as simple as folding over a corner of your stacked bills will introduce enough air at the fold to allow them to be more easily separated. Folding also push the bills off-center of the stack, leaving a slanted edge which is easier to manipulate. Crumpling new bills works not because the bills are crumpled but because the crumpling allows more air to remain between the bills.
Tackiness works well with some types of paper, but currency is made to resist tackiness. Air is your best weapon against “sticky” bills.
People seem to intuitively know this because you’ll often see people do strange things with stacked paper. Have you ever seen someone riffle a ream of paper before putting it in the printer or copier? Introducing air helps release static bonds which make it less likely that the machine will pull through more than one sheet at a time.
People who work with new currency a lot may blow along the long edge of the bills or fold a stack of new bills lengthwise. They may not be able to tell you excactly why they do these things but there is only one reason to do it - to introduce air.
Pretty good speculation and might be the reason but I’m not sure that it applies to currency. It’s easy to see how this happens with smooth paper like playing cards or computer paper. However, the surface of new currency is rough, almost gritty like very fine sand paper.
They stick in stippers g-strings much better.
Bob
Maybe some inter-locking going on with the embossed graphics.
This would be my answer too. Brand-new bills feel as if the printing on one bill is interlocked with the printing on the next bill in the stack.
As a cashier some years ago (I was dealing with Canadian currency, but the problem of sticky bills was the same), I quickly learned to use the “snap” technique on all new or nearly-new bills:
Snap your fingers.
Prepare to snap them again. But this time, put a bill between your thumb and finger.
Snap.
If it’s only one bill, it will crumple slightly. But if the bill is actually two stuck together, the snap will separate them.
Uh, where did you GET these new bills?
When I worked at Kmart, we had this stuff that was sort of like lip balm, that was made to keep bills from sticking together-you rubbed some on your finger tips.
Drug running. My clients just got a new “shipment” of bills and I have to sort all these stacks before we send them to Colombia…
(Disclaimer to authorities: I’m joking.)