During the course of my flying career, both military and civilian, I saw the demise of many aircrew trades. My flight deck crews, other than we two pilots, started out with a navigator, signaller, and flight engineer. Eventually there was only the two of us left, but mercifully our cabin crews remained. Of all those departed specialisations, the ones I missed the most were the flight engineers. As KS says above, no problem when everything worked, but a godsend, both in the air and on night stops down route; to analyse faults, perform in flight workarounds, and organise possible rectification on the ground. Worth their weight in gold!
Apologies to the others for any hurt feelings. I missed you too!