I don t believe Stan was like that because he had his memory erased a few times First of all if the doctor wanted to tweak his employees brains rather than pay unemployment or get sued etc then Stan would have had to submit to the procedure There s no way that the doctor could ve done the procedure to anyone without their consent and no way that he could ve tricked anyone into erasing their memory Even if Stan wanted to erase some of his memories about something else the doctor couldn t have gone behind his back and erased different memories All the memories that were to be erased had to be mapped before the procedure