XP (Extreme Programming). Everything is done in teams, with multiple meetings per day. You work in a set of low-walled cubicles. No code ownership - everyone makes changes everywhere. Impossible to concentrate, to get into the code for complex changes. Managers love it because they get a constant flow of status reports. Weak programmers like it because their incompetency is hidden by the team. Good programmers hate it.
This was too big of a change for me. For 27 years, I worked (mostly) in quiet, solo offices with the door shut, designing, developing and maintaining programs for years. I generally knew the code inside out, since I was the only person working on it. On a perfect day, I would get in at 0530-0600, work 8 hours, not open my door all day, and leave at 1330-1400, and I had a lot of perfect days. I could not handle the new 'social' programming.