To create a meaningful and engaging film or play the following questions must be easily answered by the protagonist - what does he/she want, how bad do they want it, and how are they going to get it. The plot then centers on overcoming the obstacles and challenges faced toward reaching the desired goal. Of course the higher the intensity of the protagonists want, the more powerful and convincing the actor will be. And the more challenges faced and overcome the more appealing the storyline.
The actors role is not that much different than real life. Our decisions to want something, and to want it badly ultimately dictates the roles and strategies we play in order to achieve them. Invariably life throws a continual series of roadblocks, challenges, and numerous obstacles on our path to our desires fulfillment. It seems as if a form of Murphy's law is continually in effect to obstruct the intended end result.
Any goal worth achieving will have countless resistances to overcome. That is a given. The most critical part of the whole scheme of things is the answer to the question: How bad do you want it? The more intensity you can associate toward your desired outcome the easier it will be to muster the will necessary to overcome the impending obstacles surrounding your goal. If you can't say with 100% conviction that you will do absolutely anything, that you will sacrifice anything to achieve your goal, then all obstacles encountered along your life path will scare you to death and leave you helpless and crippled; usually leading to acceptance of conformity and complacency.
The bottom line is this - to be taken seriously, to have the best chance of success, and be believable you must be convinced you can have what you want, and have an internal intensity that shows through your actions. Someone who actively is doing something to accomplish a goal is more believable and more certain of success than someone who only wishes or postpones. Lack of action means lack of belief in yourself.