What is more difficult - to think or to do something?

I always ponder what is more difficult? To think of solving a problem or dealing with a situation or simply doing something to attack the problem or situation.

I have observed over several years when I worked with developers of different levels and come away with a view that is more difficult to get someone to think (as in an analysis or design). It seems most developers are only too happy to do something whatever comes naturally, which may or may not produce the best solution.

Why is it harder to think? I wonder.

Recently, I come across an article which reports some experiments to study what is habit and how it influences one's action. Perhaps this is the answer, to think requires more mental activities and needs to overcome habits, which may not directly applicable to the task in hand (close but not exactly). Allowing the brain to select the right chunk reduces the brain activities and put oneself into an almost automatic mode.

But like many things in life: it is much easier to form bad habits than good and this increases the chance to apply bad habits than good resulting in inferior performance.