A few days ago, we have made an XP meeting in the company to let all people in the team (developper, analyst, tester, ...) express their feeling, what was working good or less good, what we should impoove, ...
And one developper has said that. For him, in XP, "each developper must have its own bottle of water".
I will try here to reformulate (and translate) what he has said.
"For me, in XP and in pair-programming, it's important that each developper has its own bottle of water.
A few years ago, I was working with handicaped people and we have done an exercise one day, asking to valid people to seat on the wheel-chair and so be at the place of handicaped people. One assistant/helper was doing what he has always done with handicaped people, pushing them in the house. What was happening ? At the first turn, the assistant turned in one direction as he has always done, and the "fake handicaped" was so surprised as he was expecting the turn. Later on, arrival on stairs and starting to climb them. The guy was simply astonished and afraid.
Let's stop the exercise, and do it again, differently, asking to the helper to always speak and explain what he was doing before doing it.
Now we will turn to the right. The "handicaped" guy was of course not surprised. Let's now climb the stairs. Ok no problem.
What's the point of that ? When you speak and explain what you do, or what you want to do, the other guy is never lost and can follow you easily without any surprise and without any fear.
And the parallel with Pair-programming ? Of course we won't compare one of the two developpers with being handicaped, but one of the two is not typing and thus doesn't know the minds of the writer and can be surprised (and easily lost) by what is colleague is now doing.
To avoid this kind of situation, it's important to have each people in the programmer pair speaking a lot of what they are currently doing and their idea, what is their goal, how to achieve it. It will lead to a good cohesion between each developper and the team will be more concentated and efficient.
Of course, as we must all speak a lot, we'll get thirsty and so, we each need our own bottle of water."
I find this example quite interesting because it represent the feeling that the copilot is having sometimes, not knowing where the pilot wants to go. So let's all speak more ! (in a productive way!)