It almost never makes sense to play for the last 5% of something; it costs too much. Getting 90-95% is relatively easy; grasping for the last 5-10% usually results in losing some of the 90-95%.
When I was a corporate bond manager, and doing my own trading, I had a first question in dealing with any broker: Am I getting a good deal? If the answer to that question was “yes,” then the proper response is “Done.” Don’t haggle. Even if you get a slightly better deal, it will damage your reputation. The best reputation to have is between “reasonable” and “tough.” Tough is worth more when you are driving the deal. When the deal is offered to you, and it is a good one, reasonable preserves your reputation as a fair negotiator.
You never want to be seen as a pig. Once you seem to be a pig, opportunities dry up. The guy who followed me after my time as a corporate bond manager was a pig, according to my brokers, and as such, the ability to do deals suffered.
This is true of much of life. In negotiation, leave something on the table for the other guy. You want to be able to do more deals afterward, and a reputation for being tough but fair is the gold standard.
Kids play for all of the marbles. Intelligent adults play to win a competent fraction of the marbles. That is an intelligent way to view many aspects of life. And so I encourage you to play fairly, but cleverly, for your share.