I have come to really dislike lessons - love anecdotes, though. A 'lesson' taken from a specific context and applied under different circumstances is, in my opinion, just as likely to harm than help. Some of the 'rules' may be completely arbitrary but work because Valve has some great people. Others work because Valve is Valve and wouldn't work anywhere else.

I wish sometimes people would just tell the story, and not try to distill it down to lessons for everyone to follow.