I really like this question.
Some I’ve seen:
-Skeptical it’s really the best practice – just cause 1 person in org says it doesn’t mean true
-Lack of impetus to move – may be a best practice but is ours bad enough that worth changing
-Our agency is different – don’t trust that best practice – they have different mission, size, etc
On a personal level, I worked at an agency where a group of people brought in best practices on Project Mgmt. And I’m thinking why I and others were skeptical. Some reasons:
-They hadn’t got our buy-in. Just felt rammed down throat. Lots of us had our own “best practices” they never asked for
-We weren’t invested. It wasn’t our problem so our incentive to change was lower