Know your stuff. That makes it easier to avoid nasty surprises, such as a contract coming up for renewal with no clauses capping price increases in it, when you have allowed yourself no time to renegotiate anything.

You need to understand what you are buying, and why, how it will affect your business, and what the potential risks are. That detailed understanding may be beyond the scope of a procurement department.

Not always. You should not always think you have done a good job. You will not always be satisfied. If you are, your expectations are too low - you could do better.

I was given materials that show, for want of a better word, 'kiddy porn,' but they also show they were obtained, in part, by the mother and with her name on them as the person who called these up from the computer. Now I don't know how they got on the computer, but my client has adamantly denied some of these materials, and the other materials I just won't bring to your attention.