First off, quick refresher - what is negotiation?
Good negotiation is about discovering things you value a low amount that the other party values a high amount, finding things they value a low amount that you value highly, and exchanging. I wrote about this in "How to Avoid Exchange-Based Relationships" -
A lot of people don’t understand good negotiating. They think it’s about getting the best price – no, no, no. Good negotiation is about figuring out what you can offer that’s worth more to the other person than you, and what they can offer that’s worth more to you than them.
it’s okay to have pure exchanges sometimes, like if you’re just buying something once. But if you can transcend that, move it beyond the exchange and into looking out for each other, that can be a beautiful thing.
It's not quite an axiom, but it seems like people unused to money who come to have a lot of it, shortly thereafter have no money again.
It's easy to understand why someone who wins the lottery and fritters it away goes down that path, but cash is just as dangerous in the hands of someone who is legitimately disciplined and working hard for their money, putting together good transactions, and building up a base of cash.
Money does all sorts of strange things to your psychology. Here are three big ones:
*It makes you think you're smarter than you are: when you've earned well, you tend to think it's because you're brilliant. You systematically underestimate the effects of market conditions and being in the right place at the right time, both of which can be tricky to replicate without large amounts of experience (and, even then).
*It makes you think you've reached a new level permanently: once you've gotten good at earning money, it's therefore permanently easier. This may or may not actually be true, and almost never to the extent you think with the first successes you have.