Most stressful... Whilst in Asia on a smaller ship, we had an aerial acrobatics artist come on board the morning of their show. They bought on 4 different aparatus, after being told lies by the talent agency - namely that we had a performer flying motor that could be used to hang their apparatus from. Not the case. I spent the morning beg, borrowing and stealing a chain motor (that moved at the break neck speed of 6 meters a minute)
It worked for the 10 hours we spent designing, rehearsing and teching the shows. We go to preset the first apparatus...The motor does not move. We yell out to the bar staff to hold doors, I climb up the ladder, cannot see anything wrong on a cursory inspection - and I cannot take the motor to the floor (as we did a sweet job securing it), we cannot just put in a new point as we had custom-built a stabaliser directly below the motor to prevent sway from destroying my rig. We contemplate putting on a production show instead... Nope, half the cast are drunk... We look to see if we can dead-hang each apparatus - but we don't have clearance and we don't have the time to redesign the lighting. We are now at 2 minutes to show start, and we are at crunch time. We decide to bridle some spansets to a few inches bellow the chain motor and hang the aparatus there through our stabaliser, with stage staff coming out in blackouts to change them with a ladder. We open the doors, seat the audience (950 of them) in 2 1/2 minutes, and start the show 3 minutes late.
Longest I have had though was when an actor borrowed a pair of costume shoes (without permission) and left them at home, remembered at 10 minutes and decided to drive home to get them - forgetting it was peak hour and the traffic was hell, in the hope that he would not get a written warning for taking the shoes. He arived 11 minutes after we were meant to start (and he was critical for the opening number and was wearing the costume, so the understudy could not step in), he left the theatre 11 minutes after the show without a job.