It's easy to get negative because you get beat down. You go through a few disappointments and it's easy to stay in that negative frame of mind. Choosing to be positive and having a grateful attitude is a whole cliche, but your attitude is going to determine how you're going to live your life.
The correct strategy for Americans negotiating with Japanese or other foreign clients is a Japanese strategy: ask questions. When you think you understand, ask more questions. Carefully feel for pressure points. If an impasse is reached, don't pressure. Suggest a recess or another meeting.