I got a call out a few years ago to a fault myself and two other colleagues had been dealing with all day. My two colleagues have forgotten more about the piece of kit than I'll ever know.
I explained to the first controller that we had been working on it all day and ran out of hours so we would be back on it first thing the next day. I explained all the testing we had done, the fact that I'd only be able to repeat what had been done already which would prove nothing and not resolve the fault.
It would also mean that if I was out on it all night I would not be there during the day to help my colleagues with the donkey work, whilst letting them think about the problem. He was not happy but went away.
An hour later phone rings:
"This is The Control Manager, I'm not happy with your response, what are you going to do about it"
Me (mustering as insolent tone as possible) "Wow, that's an impressive title. Nothing"
Me "Nothing, I've told your colleague everything, I won't be able to do anything productive tonight on this fault, far better to use my Oncall time for something else if it comes up or for me to help my far more knowledgeable but not oncall colleagues tomorrow"
CM "That's not good enough, I want you out there fixing it"
Me "I'm not going as I've already tried everything I know and my colleagues have spent 9 hrs looking at it today and are still no closer to a solution"
CM "What's your Manager name"
Me "It's so and so but he'll give you the same answer"
Five minutes later my Oncall Manager rings me and tells me off for not saying "Fxxx xxf!" more rudely to the CM!