Some answers to yesterday's question:
I've been thinking about this in terms of habits. Every so often my critical paths get mucked up. Everything is suddenly inefficient. I do everything wrong (dry in the wrong order after my shower, forget whether to make tea before or after turning the computer on). Why does this happen, after months of running on automatic?
Okay, so habits are good: they free the mind for important things. But habits are not necessarily optimal, so have to be shaken up every so often (like punctuated equilibrium). But what good is that if you do it on your own? Everyone else's habits and the habits of the environment will force you back into your groove.
(The idea being, the environment picks up habits from you. This is how special offers work. Lower the barrier to entry to go to Starbacks, and you go there more. Put it back up, and you still go there because your habit is now to cross the road earlier and so you're nearer it. Someone else, who used to walk in that spot at that time every morning now walks somewhere else because of your new behaviour. When you shift your walking position, you're displacing someone else's habit. Shifting back will be hard.)
In which case, if habit shake-up is a good thing but the environment puts a stop to it, then evolution will find an answer. There's not much to do about physical world's ingrained habits, but it is possible to do something about other people.
Concept: Habit-breaking days spread like a virus through the population, so everyone can shake up at once and settle into a better equilibrium. We're designed to trigger an internal shake-up of all habits if we're exposed to an external event that challenges any one of them (unexpected externalities puncture the stasis). That's why breaking one habit throws you off the groove completely, so it spreads to other people, outward and onward, and so on. I can't prove this, of course.