In a negotiation you can be too smart for your own good.  I been involved in negotiations many times where one party thinks that they are smarter than the other people involved so they develop a negotiating strategy assuming the other party is stupid.  Invariably, the other party is not as mentally challenged as expected and the negotiations do not develop as anticipated.  In some cases, the smarter party may be taken to the cleaner or unable to close the deal.

One of my tenets in life is that you can not assume people are either less or more intelligent than you are.  Some people portray themselves in a manner to achieve their best results (either superficially or in a deal sense).  I have been involved with one person who portrays himself as simple country lawyer who doesn't really understand anything.  This is a person you should be most concerned with.

So my recommendation is treat your negotiating partner with the proper respect (but not too much) and do not expect to pull the wool of his eyes.  Also remember that the goal of any negotiation is to reach a mutually beneficial deal rather than to take every nickel off the table.