So.. I don't know if anyone has made these comments.
I like all of the superstitions and refrain from using/doing them in the theater even if I don't believe in them in case others do.
I have heard many reasons for all of these and read 66% of this thread so I apologize if these things have already been said but I just want to
throw my own story / two cents into the pot.
Break a
Leg: I heard that break a
leg was started by dancers. At the end of the show, often people would
throw flowers or money up on
stage as dancers were doing their final
bows and often their legs were held out straight in a pose. The idea was to "break" your
leg (
bend it) to
pick up money / flowers showing that you've done a good job. The idea is wishing someone good luck by saying break a
leg, as to get a favorable result from the audience.
Whistling: I would imagine that during a show, there would be less need for the whole whistling as the show was set up and the person running knew what was coming. However during a
load in, when they probably hired more crew to hang everything and get it set up, they probably used whistles to help in the process of weighting, hanging, and otherwise rigging the drops. All of these people may only work on the in and the out.
Walking under a ladder: I gave up this notion when I first started professional theater. If I can avoid it, I will. More out of personal
safety. I also ask others don't do it because they could
send the person on top of the ladder over if they bump it just right or whatever.
Safety.
Ghost Light: This is my favorite as it always leads everyone to make up a ghost which lives in their theaters (sometimes new theaters!). I like the
ghost light particularly because I have often entered a theater in a door which isn't by the light
switch and have had to make my way there in the dark.
Theater People are the best.
EDIT: After this post I realize that this is a very old thread. =( Oh well!
Love the sign that revived it.