Are You a Robot?

We are familiar with the term "gaslighting," where a nefarious character tries to convince a victim that they are losing their mind. In this story, the poor fellow who can't pass a Captcha test starts to think he's going out of his mind. Those things can be quite maddening at times to the point you suspect they were designed by robots who  have no idea what they're doing. But his co-workers seize the opportunity to convince him that he's not insane; he's actually a robot and never realized it before! Their methods are horrifyingly clever.