I was forced into it for a few months when it was hot and Agile was still XP (Extreeeeeeme Programming). I found it agonizing. I was unable to do anything deeper than code the simplest functions. Everything I "accomplished" felt shallow and I could not come up with something better until I was unpaired. Sure, I could bash out comments and boilerplate and dumb little helper functions, but the part of my brain that seems to spit out the mysterious solutions that are the point of the whole exercise was dead silent.