I'm many years out from my PhD, but still get impostor syndrome even working in the corporate world. Like a constant nagging feeling that I have no idea what I'm doing, and other people definitely know what they're doing. As long as I'm able to portray on the outside that I know what I'm doing, I'm able to achieve most of the objective measures of "success", but I still have the impending fear that at some point, I'm going to be found out...