I had a coworker with whom I did some pair programming and it was painful. He was very talkative, to the point of forcing me to interrupt him every time to come back to what we were doing. Also most of the time he made really hard to follow the code because he took every opportunity to show off his keyboard-shortcut-skills, jumping from file to file, jumping between lines of code, commenting and uncommenting code...…
2) You'll pick up his shortcut fluency in about two days of pairing ... I taught my co-founder Emacs and Clojure at the same time in about two days of pairing