At my last job, I worked with someone who had a PhD from an elite university. This person came across as very smart, had a great smile and an easy demeanor that

At my last job, I worked with someone who had a PhD from an elite university. This person came across as very smart, had a great smile and an easy demeanor that made friends of everyone. But I'm hard-pressed to remember a single accomplishment or even lesson learned on the job. Training was a total non-starter, just blank stares, and I'm not alone in this assessment. It's like this person was just a professional job hopper. So is that person the idiot, or were we the idiots for falling for the act?