Literature
Ladder 'Bout to Fall
or, Five Superstitions on the U.S.S. Enterprise
Sandwiches
It's not that he considers the sandwich itself unlucky; Scotty loves his sandwiches. It just that when the sandwiches run out that he starts worrying. For example, the day he got into that huge debacle over beaming Admiral Archer's beagle to God knows where?
The replicator stopped making sandwiches that morning.
So Scotty always asks for a sandwich, because he knows that if he doesn't have one, something will go horribly wrong.
Catch Phrases
There are certain things that certain people say at certain times - or all the time - that just reassures the crew. For instance, Leonard '