Most critical
Five Thirty a.m. and all was quiet in the ACC; the managers, supervisors, techs and assistants would all start arriving about 6. The IT techs had recently shown us the secret way to put video games on the sector radar displays. Now we couldn't get the bloody video games off the Departure display or the East Sector display. The only solution was to disable both and complain loudly to the arriving dayshift about the display failures . . .
I guess a close second would be the time we found out that a Danger Area was hot with SAM firings (USA Airspace) after we'd been running aircraft through it for 40 minutes . . .