It's their job, stop acting like its personal. Usually they have to verify everything over a 20, sometimes in more than one method, such as the UV light and pen and holding it up for the watermarks.
I usually make it a point to be more thorough with checking if people make a fuss about it, or crack that tired old lame as hell 'I just printed that' line, which by all rights permits/ requires me to get as many of their details as possible and notify law enforcement (its technically admitting to counterfeiting money even if it's a joke) and my store policy (from corporate) is all bills above a five are to be at minimum checked with the marker.
There's actually a much easier and more subtle way to tell if you have sensitive fingers. Take literally any US bill and gently rub the portrait's jacket. It should be very slightly textured by a printing process called "intaglio"
https://en.wikipedia.org/wiki/Intaglio_(printmaking)#Current_use
Not all parts of the bill are textured; the only parts of the bills I know of that are guaranteed to be textured are the jackets. I suspect that the borders are also supposed to be textured but I can't tell because I only have older bills that have been folded to shit.
https://en.wikipedia.org/wiki/Intaglio_(printmaking)#Current_use
Not all parts of the bill are textured; the only parts of the bills I know of that are guaranteed to be textured are the jackets. I suspect that the borders are also supposed to be textured but I can't tell because I only have older bills that have been folded to shit.