Not so much a question as an example of the problem, perhaps.
I was riding "up front' some wee while ago, and we received a clearance, descend to.. level by … The F/O duly tapped it into the FMS. A short while later ATC asked for confirmation, were we going to make the level (obviously due crossing traffic or some-such)? "Affirm", with the confidence its in the FMS. Then another request, for confirmation, because of other traffic. "Affirm, its in the FMS".
With about 1 minute to the restriction, the FMS pulled the plug, the aeroplane dropped like a stone, and we sailed through the restriction point spot-on.
However, I don't think that was what the controller wanted, and I don’t think the pilot perhaps appreciated the reason why the controller was becoming agitated.