“Everything is negotiable. Whether or not the negotiation is easy is another thing”. Carrie Fisher.
The hardest thing about negotiation, in my personal opinion, is maintaining the ongoing discipline of imagining how the other side sees things.
Honesty called for here. How many times have you ended up in an argument or dispute only to later find that the other side really did have a good point? Maybe you couldn’t process this at the time because you were against the clock, because it was poorly explained, or because you just didn’t like each other. Whatever the reason, a deal was not done when it could have been. Like you, I have been there many times regretting that more wasn’t done in the deal when it could have been. Richard Holbrooke records how WW1 started because of a botched negotiation. It needn’t have happened. Quite a sobering thought.