The first one was not a bad person by any means, but had no social skills, no ability to communicate and often just forged ahead building great stuff on his own. Entire areas of the software were entirely conceived and created by him, and it was difficult to even grasp what he was doing while pair programming with him. In a day he would write more tests and get more coverage than the rest of us would create in a week.

The second one had come from a FAANG-ish place where he was extremely successful, but didn't want the money or stress. He was extremely kind, considerate and great at communicating. Pair programming with him was a joy and he helped everyone else on the team grow. I'm confident he could have created entire regions of the software on his own, but he knew that wasn't the right thing to do. He would often ask questions until someone else on the team could solve a problem, even though I'm sure he knew how to solve it easily himself.