In my years of working in flight test at Edwards and Hill AFB's, I found that test pilots usually fell into one of two general categories (although there were exceptions in the middle):
A. The good and the best test pilots were not only very competent but were very personable. These were guys who could light up a room anywhere they went because they didn't have any axe to grind, nothing to prove, an easygoing teamwork spirit, and more often than not, a sense of humor. These guys had a steady gate and did not panic under pressure. They followed the flight test cards, suggested improvements when they had some, and would work in other test points on the fly when they could. If they made a mistake, they fessed up immediately & felt genuinely bad. These were the kind of guys you wanted to work with, and have a beer with at the end of the flight test work day, back when they allowed beer in the flight line pilot's refrigerator (and you could smoke anywhere except the hanger).
B. The mediocre or marginal test pilots were somewhat competent, but not very personable. They were not very teamwork-oriented & were edgy at meetings and emails. They couldn't keep their cool and got angry when things didn't go right. When not able to complete flight test cards or the tasks, they would blame the test cards weren't clear, in error, or was some engineer or other person's fault. These were the kinds of guys you dreaded working with and they thought they were always right and you are wrong & no matter what you say they always act threatened. These were the pilots you never wanted to have a beer with at the end of the day, but if you wanted one, you had to hang out with them anyway and make the best of it. But they were always a pain in the arse to work with and often mean or un-professional.
Another valuable lesson I learned in my years of flight test, NEVER speed on a U.S. AFB road. Even in the desert.