Expression: Play it by ear

If you play it by ear, it means that you don't have a plan of action, you improvise as you go along.
What do you think of this way of doing things? For some people, preparing a plan and folllowing it are important or necessary. Others like to play it by ear. Some prefer a mix of the two approaches, and I think I fall into this category. When I plan a class or presentation, I prepare an outline and some resources, but I try to be present enough in the moment to play it by ear if the situation seems to ask for it. Sometimes the best classes are the ones which deviate the most from the plan!
What about you? Do you like to play it by ear?