Once I got into the first interview, the texture of their requirements began to change. The notion of their need to change one individual became apparent. The problem at hand became to identify that person, if possible.
The second interviewer was normal and benign. He was pleasant and nearing retirement so he was marked off the list of possible hostile engineers.
The third interviewer seemed like he could have been the hostile engineer. He stated his beliefs for continuing to use old technology and procedures then, each time, he flashed a very strained grin. It was eerie. He was too young to have poor attitudes about new technology and procedures.
Hostile engineer's boss took me to lunch and clearly identified this man as needing help with the 21st Century. Bingo! He was difficult to deal with and they could not do anything with him. They wanted to know if I could change him. The position I was interviewing for was below everyone else's I had met that morning and was not management. It was engineering.
The afternoon interviewer was an engineer and felt he had been overlooked, maltreated, etc. thus was bitter and resentful. He was so angry, he spilled the beans on everything and everyone. He confirmed all of my suspicions. These managers set out to find a technically savvy engineer that had also worked with difficult people.
Should one beware of managers with very strained grins? Perhaps. The ones to truly beware are his managers for procrastination on solving a difficult problem.