Based on Murphy's Laws of Combat Any resource you use to modify damage right now, you'll need later, too. Anything you do can lose you the game, including nothing. The strategy you've assured yourself is foolproof, will only be such, until you show it to someone else. The easiest prizes always have some drawback. Disruption Trainers, won't. No matter how long you've worked on a deck, someone else has already made a better version. Against a worthy opponent, your path to victory is never a straight line. Count how many turns you think you have left until your opponent defeats you, then reduce that number by one. Your impenetrable defense is only such until your opponent figures out how to penetrate it. Whatever you need to win a mirror match, you will inevitably not have in your hand. For every reason your new deck is good, there are two or more reasons your deck won't work. Probabilities established during practice matches never hold up in tournament matches. If you're winning too easily, your opponent has a surprise. You will remember to perform a critical game action, two seconds after you say, "Pass turn." Confidence is an asset and a weakness. Build a deck to beat all of the standard strategies, and you'll get paired against mostly rogues. "I'd rather have one and not need one, than need one and not have one," doesn't apply when you are limited to only 60 cards. A series of easy opponents will give you wins, but also give you horrible Opponent's Win Percentage. Imagine the worst possible scenario for you and the combination of cards your opponent would need to access to make it happen. Then, realize how unlikely that specific combination of cards is. Then, imagine it happening anyway. A deck that is successful in your friend's hands, will fall apart in yours.