Mood of the Market. I love a discount. It’s a serious rush-generator for yours truly. Yet and still, there are several things I just don’t believe in cutting costs on. Attorneys, for one. Surgeons, for two. Yoga pants — some things just need to work, perfectly, every time, and the discount version causes bad results. And I feel the same way about overconfidence. Much of the time, it actually serves our interests to take a reasonable estimate of our abilities (which we tend to be overly conservative about, as a rule), and jack it up 10 or 15 percent: When we go into a sales pitch, or start a business, say — maybe even when it’s time to approach the man or woman of our dreams and start that first, terrifying conversation.