You're not, ex nihilo, going to create within yourself some sort of relentless will to create. Worthwhile endeavors are hard. Becoming more fit. Building a product or company. These goals aren't fully achieved in one inspired surge of energy. And our brains seem to be wired towards amusement after our basic needs are met. Intentionally doing hard things is the evolutionary equivalent of repeatedly touching a hot stove; your brain's going to keep telling you to knock it off.
So, you've got to take advantage of what we know about our brains to "trick" them into doing work. Here are a couple things to read that might help you figure out what "hack" will work for you:
1) http://www.nytimes.com/2012/02/19/magazine/shopping-habits.h... is an article about shopping habits, that contains a couple of interesting gems about how companies actually do the same thing ("hack" your habits) in order to bring about desired consumer behaviour. It's adapted from the book: http://charlesduhigg.com/the-power-of-habit/ which I haven't read but suspect just has many more examples.
2) http://www.wired.com/magazine/2011/06/ff_feedbackloop/all/. Figure out a positive feedback loop that you can take advantage of. For me, when I was working on a book, one thing I did was build a script that would count the words, make a note of the count in a journal, and post an update of my progress to my Facebook wall. I'd get encouraging comments from my FB friends, presto: positive feedback loop. Related: What gets measured improves. What gets measured and reported improves again. I'm not sure where I'd heard that quote, but its proven true for me.
3) Along those lines: "Don't break the chain". http://lifehacker.com/5886128/how-seinfelds-productivity-sec....
Good luck. It's a lonely lot of work becoming productive.
Reading the first article was cathartic: I have never thought about the deconstruction of habit forming before.
I will implement these suggestions and create a system to follow based on them.
Here's a link: http://www.youtube.com/watch?v=D1R-jKKp3NA
I still allow myself time to relax/slack off, but if I had intended to only watch a few episodes before getting down to working on something I'm passionate about, and then have the urge to just do the easy thing and keep watching instead of doing whatever I'd planned to do, I remember that my time is slowly running out and if I don't take steps to achieve my dreams now, then I will likely never achieve them before there's no time left.
This applies to everything in life, not just work. Travel, falling in love, learning new things--you name it--everything is affected by how limited your time is. Time and your body (there's a direct relationship between them) are the most limited resources you have, and even if you strike it rich you can never rewind the clock. This is what motivates me more than anything else to get shit done. On a related note, once you realize just how limited your time is, you realize how pointless it is to live your life for other people or be constrained by dogma. Anyway, at this point I'm just rehashing the speech, and Jobs says all this much better than I do. If you haven't seen it yet, go watch it. If you have seen it, go watch it again and listen very carefully to what he says.
I have a strong urge to not be the kind of person who tells people he's going to do something and then doesn't. So if I really want to make sure I accomplish something, what I do is tell a bunch of people about my goals and set a realistic date where I want to have met some certain metric, and then I ask them to ask me about about my progress on a regular basis. If I tell enough people, then usually at least one of them remembers to ask about every other week, and after awhile I'll go "shit, if I don't actually do this, I'm not going to reach my goal and everyone will know." It's basically manufacturing peer pressure for a positive purpose. It's really scary to do this (at least for me), but that's also what makes it effective.
Fanatical resolve sounds less than desirable, I'd far rather settle for 'consistent'.
If you're interested in building a company it will take several years to decades; take your time.
Yesterday, for instance, I sat down and coded for a few hours, when I could have been out drinking with friends. The surf looked crap, but I decided I wanted to get out for a surf just to get my head away from the code for a bit. Turned out to be a great and unexpected session. My small reward for doing my work.
Seriously, I think the only way is unhealthy emotional involvement.