Along with the basic rules, most CCGs have a collection or errata, a bunch of situational rulings to clarify when two cards interact in a confusing or contradictory way. As the game goes on, and new cards are added, the errata ends up dwarfing the original rules, and some phonebooks as well. And this is when you have paid R&D workers laying down the most specific, rigid effects and definitions they can (usually as a result of the Customer Service's urging).
Now apply that to a constantly evolving, mutable game of vaguely worded, cryptic commands, that usually has a sizeable amount of cards to work with. Like, say, one thousand?
Bizarre and unexpected card interactions pretty much make up a basic strategy of 1000 Blank White Cards. You'd be a right party pooper if you just responded to dominating plays by making the "This Card Can Remove Any Card Regardless of Any Other Card" card (and not to mention a victim of an insufferable lack of imagination). But by combining the Victory Dance card that's been taking up space in your hand (Every time this player gains points, they must do a happy little dance) and creating the No Fun Allowed card (Any displays of happiness, elation, pleasure, joy, jubilation, or unsadditude will be penalized with -700 points each), you can turn your opponent's perpetual-points-producing-combination into a constant stream of pain. The rest of the other players will probably find this so amusing that they will do whatever they can to continue the player's dance of doom.
The best times, however, are when a silly, previously made card which never really achieved anything (what's the point of removing all the non-card items on the table if nobody even puts their drinks down?) suddenly becomes the exact weakness of a current dominating card (such as removing the entirety of the Post-It Army's Post-It Tokens, for example). This usually results in stunned silence, laughter, and then a dissolution of the game once the main tactic has been blown wide open.
Unforeseen Consequences of Point InflationEdit
-->Can be used once per round at any time
-->Damnation -- Costs 60 magic. Can suckbox a card.
-->Soul Drink -- Gain 3 magic in exchange for cutting your score in half.
That first ability is very powerful but is balanced by a high cost. Now, you don't need to be a genius to figure out what's going to happen if, say, a few games later, people had thousands of magic; that's right, this wizard would be murdering cards left and right.