I *totally* have this problem.
Once I've identified something I want to do, I go out madly and energetically collecting all the essential elements, preparations, read up on it extensively, acquire, acquire, acquire... and then... don't actually attempt it. Or, make a half-hearted attempt, but can't make myself cough up the self-discipline to stick to it. wtf? I'm really good at preparing and anticipating, but very poor at actual application. =(
It seems like I fear taking the risk to DO something, lest it fall short of my vision. Or, I haven't the patience and perseverence to build up the skill required. This kind of thing normally occurs in regard to something like an artistic project. I can't tell you how many novel hobbies I've sprinted into, just to drift away from them when encountering frustration of less-than ideal outcomes