My only dice superstition is that for each new game, I get new dice. Weather I am a player or the GM, every time the group starts a new campaign, changes rules systems, or tries a new setting, I buy a new set of dice.
This habit originally started as a way to discourage myself from changing characters too often. When playing in a long running game I would get an idea for a new character and want to play it. Our group rule at the time was; all new characters start at beginning level. I was always behind the power curve. To limit my character hopping, I instituted the personal rule; New character, New dice. At the time we were on a pretty tight budget. The money aspect was a real deterrent to changing characters too often. The mind game worked, and I learned the joys of playing a more long term character.
Then I started GMing on a regular basis, and my gamer ADD reared its head once again. I would get excited about a new system, or GURPS would release a shiny new source book, and I was off the the races. Often I would spring the new game on the players without warning and with too little prep. THis bad behavior caused many a game to crash and burn. So, I put the rule back in place. New game, New dice. While I can afford new dice more easily now, the effect has been the same. I take more time to plan and prepare for a new game. I give the players more warning when changing things up. In general it just slows the process down, preventing rash decision making.
There is an up side to this little quirk. Each set of dice is like a little souvenir. I can look at a set of dice and, in most cases, remember what game or character they were attached to.
Although we are a couple of weeks into the new game, I have just now gotten my new dice set. The delay was accidental. I ordered some dice at my FLGS, but due to back orders and then discovering that they were no longer in production, they never arrived. I purchased a set from my next FLGS, and now I feel as if I am finally, completely, really and truly ready for tonight's session.
my new dice (and my dollar store dice tray)