The problem though is the Agile Industrial Complex and "thought leaders" who have pushed this as a religion on the industry. I enjoy pairing, and the excitement of two minds working at the same problem in tandem is an experience to be relished. But give it to an Agile snake-oil salesman, most of whom gravitated away from programming a long time ago in favor of making money training others in how to program, and they'll wield it as a weapon by prescribing the only true way to work.
XP (in its traditional sense) doesn't scale past 8 developers anyway. Anybody selling you XP for a team of 500 is someone to be wary of ;-)
There are pains and giving folks the opportunity for change/rotation is refreshing.
Software is a team sport, its a weak-link game where we must communicate and empathize in order to see clearly (often past our own egos) in order to pull one-another up.
I was fortunate that good pairing hygiene was a focal point. Without that it can be disastrous mentally and ruin the experience for everyone. It turned into a highly collaborative sport at that point.
I am a hugger naturally but when I run into those pairs I went through the trenches with, it is a brother/sister hug. Best time of my life.
However, we had a few guys on our team that really didn't like it. They left and I don't think less of them in any way. It's a different way to do things.
As for the "repetitive work" aspect: the most successful XP project I did was a collaborative sketching application using pen input with automatic shape recognition: somewhere around 2000 (when did MS put out those pen based computers??? -- We did it for their unveiling).