Cultural expectations in a company coevolve.

People do things that they've seen others do, and that have seemed to have worked for others.

Social systems of norms are alive, and shockingly resilient.

An example: Google's peer bonus program.

It allowed any employee to give a $200 bonus to any other employee for just about any reason.

There were a few limitations:

No more than 12 a month.

The recipient's manager got an opportunity to veto anything inappropriate.

You couldn't peer bonus someone who recently peer bonused you.

Every year, some enterprising new APM would figure out a "triangle peer bonus" to create rings of peer bonuses that skirted the rules.

But whenever an elder APM heard about it, they'd say "that's not cool man," and the new APM would cut it out, no formal rules necessary.

With that little bit of social energy, the thing went from a "I'm cleverly exploiting a loophole" to "I'm undermining a system everyone values."