The Computer is Your Friend. The Computer will help you become happy...
No, no, wait. Not that Paranoia. This post is about a useful attitude for people working in technical theater.
There are places and times where mistakes are recoverable. Early in the design process, early in the build, you can stop, toss out the failed experiment, and try again. But there are also -- in time as you get closer to opening night, and in safety as you get closer to the actor or audience -- that error or accident is going to hurt a production, or worse yet, a human being.
An expression among certain engineers is "Physics never sleeps." It is a rephrasing of the better-known "Murphy never sleeps." The rephrasing is to point up that humans can make lots of mistakes, can forget to account for a shear load or incorrectly calculate a thermal expansion, but the universe is never caught napping. It will always act, inexorably, whenever you give it an opening.
Much of theater engineering is not based on any rigorous analysis or calculation. Much of it is not applied with any real understanding of the underlying physics. What most theater technology is, is a set of robust empirical solutions. The basic 2x4 framed platform, for instance, works because it is overbuilt. The excessive strength of the construction usually makes up for eccentric loading and other misuse of the structure.
This means, however, there is no analytical tradition in theater. There is no equivalent to what they teach engineers, or the school of Defensive Driving; no established school of theatrical thought that makes it its business to check the work before the Universe checks it. There are established procedures that check to see if something is functioning (pre-show checks, for instance) but none that test if something is on the verge of failure.
That's why I like to be the professional paranoid on a build.
It is easy to characterize always expecting the worst as a negative. This is why I try to restrict what I actually communicate to two categories; those potential failures that are easy to fix, and those potential failures that are likely to cause human injury (or expensive damage).
The first assumption you have to get rid of is that there is such a thing as foolproof, or failproof. No matter how sturdy the hardware, base your analysis upon the assumption that it will break anyhow. Then ask what happens. It is this looking forward, the "what happens next?" that is most not done. The few times that people may look at a piece of hardware or a piece of a set or a bit of wiring with suspicion, they almost always look at it in static terms. Is it holding up? Does it look strong enough to keep holding up?
What you have to do is think through an unfolding accident. Visualize where the stresses go, visualize the worst-case. WHICH WAY does the platform fall? WHERE are the loads when the first turnbuckle fails? WHICH LEAD is the "hot" if that other conductor gets severed?
Inevitably, you will discover situations in which two high-probability conditions, which taken in isolation cause low-impact accidents, combine to make a severe accident. IF the lightweight hardware fails AND an actor is standing on the bad corner at the same time, then...
Being paranoid is also checking, checking, checking. Don't rely on memory. Don't rely on co-workers. Don't expect that since the switch was "off," it will remain "off" while you work on the exposed conductors.
More than anything else, assume stupidity. Don't flip a switch, put a piece of tape on it and write "Do not use." Because as sure as apples fall from trees, someone is going to decide it doesn't apply to them, it is an old piece of tape and the thing was fixed years ago, or they are smarter than the person who put the tape down and THEY can make the switch work by flipping it to the "on" position.
Leaving you screaming and holding on to a bare wire on the other end. Or starting a fire as a fog machine with no water in the drum is energized and left heating up in an unobserved corner.
Get into the habit of physically denying access. Lock out breakers. Remove buttons. Unplug equipment. Don't trust to tape and labels. And never, ever trust that no-one will mess with it because no-one is supposed to go into the booth anyhow.
Plan to be late. Plan for something to come up; the set ships late, the choreographer changes his mind, there's a substitution in the cast, whatever. Don't ever start a plan with "We'll pull an all-nighter on Thursday and be ready to open Friday." Front-load. Build all you can early, so when things go wrong there are hours left in the day you can add!
Use all of your senses. Be an actor...move through the set handling things to discover if there are stumble hazards or sharp edges. Listen for sound wood, taut cable, loose hardware. Smell for overheated or burning things.
And this whole post is terribly rambling. I'll blame the long shifts I've been on this week. But I'll try to conclude with a couple of specifics.
Always assume the mic is live.
Never put your head in front of a monitor if you aren't in control of the situation. One careless muso, one blare of feedback, and you will be wearing a hearing aid for the rest of your career.
When in doubt, use dynamics. When a cable with Phantom Power goes bad, it makes a horrible pop that can destroy speakers. Hand the clumsy singer a dynamic mic instead.
Never leave a radio mic up when you aren't at the board. You really, really don't want a "Police Academy" moment.
Never allow any liquid to get above the level of the sound board. If you MUST drink coffee in the booth, sit way back and lift it as low as possible so WHEN you spill it (which you will!) the splash doesn't reach the expensive electronics.
Always stick a spare cable into your under-stage run. Always leave a free channel on the snake. Always leave a length of XLR in the pit until you are SURE all the musicians have finished re-arranging themselves.
Dress cable from the dead end. You will almost never have to move the wall but you will frequently have to move the mic so you want the slack THERE, not forty feet away where it does you no good. Don't tape it until it has been tested (if at all possible -- in high-travel areas, safety trumps efficiency).
Test the mics constantly. Use your PFL when the band returns after intermission, while there is still time to remind them to plug back in or put the mic back where it belongs.