Anybody who had even looked at a pocket protector is well aware of the old television series Star Trek. A common occurrence on this show is that Captain Kirk would sit in his command chair (that looked remarkably like a proper Lay-Z-Boy recliner) and order Mr. Sulu to raise the shields. The reason for this order was to keep a hostile Klingon ship from popping a photon torpedo in their ass. While the idea of protecting military vehicles from attack with some sort of force field is still something in the realm of fantasy, poker players have their own form of a shield.
In a game that runs for days and days, such as the Main Event of the 2006 WSOP, it is very important to not only start each day reviewing your plan of attack, but renewing it frequently. When this isn't done, you end up like player Dmitri Nobles.