Impulse control
Some things one encounters in life are seductive, but dangerous to pursue. Consider the legal concept of the Attractive Nuisance, for instance. Oftentimes, the attractive object has actual benefits, whose siren call are liable to wear ones defenses down, despite all the rational arguments marshalled against the object.
In my experience, the most successful way to fight off the Attractive Nuisance does not rely on rationalization, but on fighting emotion with emotion. If you look hard enough, everything has a flaw of some sort — something unappealing, imperfect, or undesired about it somewhere, perhaps in the most minor of ways. Concentrate on this failing with all the attention you have, and the negative perception will eat away at the positive ones, and if you are lucky it will be enough to hold you back. The fancy new gadget has low battery life, the good-looking individual has hands which are too big or too small, the door to the new place to live is hard to shut. Sometimes, you have to work pretty hard to perceive or to imagine a blemish, and when comes to mind at last, it arrives as a relief.
This is not a strategy that is good to use for everything indiscriminately, because that is a recipe for sapping all enjoyment out of life. That is what Oscar Wilde meant when he defined a cynic as "someone who knows the price of everything and the value of nothing." That's no way to live, in my opinion. I prefer to bring out this gambit only in the face of great temptation which my left brain recognizes as being a quick path to great danger.
Now, I just have to come up with a short and catchy name for the technique. It's something like "sour grapes" but with intention behind it. Any suggestions?