I learned a valuable lesson in poker: never underestimate your opponent. The moment you do, you’re set up for a quick and humiliating loss.

The same is true in business negotiations. Although a good businessman negotiates for a win-win (doesn’t want to defeat or to be defeated), its easy to think that you’ve got the best cards. Maybe you think you’re smarter, better prepared, or have an edge in market intelligence that will lead you to win.

Every time I’ve been in that position, I’ve lost. The most humiliating loss came about 2 years ago when I thought I could outsmart a 15-year veteran. Instead of getting a higher price (which I did for 2 months), I lost 100% of the business because they cancelled the project and quit buying my product altogether (the price was too high.) It was embarrassing and painful and an experience I never want to repeat again.