You do not have to spend a lot of time and effort on those who strongly resist change. You only have to help and protect those who want to change, so that they are able to succeed. Put another way, your job is not to plant the entire forest, row by row — it is to plant clumps of seedlings in hospitable places and to nurture them. As they mature, these trees will spread their seeds, and the forest will eventually cover the fertile land. The rocks, will, of course, remain barren regardless. … once you have figured out who cannot be converted, you should not waste more time trying to persuade them.

— David Hutton, The Change Agents’ Handbook