Trully, just a thought is not enough

Did you get in a situation when you have a great thought in your mind, you know that if you would do it on that way it would be close to perfectionism and still you dont do that or you do it otherwise. Why? Os it laziness (again)? Or some kind of 'i can do it even better mechanism? I doubt. It is just because we (i) do not have enough will to take the thought into our hands and realize it. Of course, laziness comes within. What is then laziness? Something what we can put away? Is lazyness boredom? Who is not lazy? Or is laziness lack of energy? Or just simple, 'i dont want to do that right now' thing?