I think I get what you're saying here in that it's not the best use of energy to stay where you don't have a fit, however, I did want to offer an answer to the second part of your question.
An attitude that casually accepts moving on in search of the "greener pastures" may leave someone perpetually on the move searching for a mythically green pasture while never developing the skills to maneuver inevitable difficulties within any social relationship.
I do think sometimes moving on is best, however I also personally think the moving on in hopes of something "greener" should only be done after careful self examination about how realistic one's expectations are and if possibly the change is more effectively made within rather than without.