Yeah, PC as 'Player Character' is normally used like MathiasZaman said to mean "person who does things that influence the world in a significant way" or 'the person around whom things are revolving".
The way you are using the term seems way, way too broad to me.
Welp, few PCs have their stories start before they're born, so everybody who ends up as one has gotta start somewhere. I'm already a one-in-a-million person, due to being a cryonicist; all I need is a few more orders-of-magnitude of competence, and I very well could end up as someone who influences the world in a significant way. (Possibly by becoming the first mind-upload, and using my first-mover advantage to become the most populous being in the solar system...) But given my state of being as of the end of last year, it's going to take some time and effort to get there, and any trick that can help keep my motivation high is worth asking for. So - here we are.
"Cryonics has a 95% chance of failure, by my estimation; it would be downright /embarrassing/ to die on the day before real immortality is discovered. Thus, I want to improve my general health and longevity."
That thought has gotten me through three weeks of gradually increasing exercise and diet improvement (I'm eating an apple right now) - but my enthusiasm is starting to flag. So I'm looking for new thoughts that will help me keep going, and keep improving. A few possibilities that I've thought of:
Pride: "If I'm so smart, then I should be able to do /better/ than those other people who don't even know about Bayesian updates, let alone the existence of akrasia..."
Sloth: "If I stop now, it's going to be /so much/ harder and more painful to start up again, instead of just keeping on keeping on..."
Desire: "I already like hiking and camping - if I keep this up, I'll be able to carry enough weight to finally take that long trip I've occasionally considered..."
Curiosity: "I'm as geeky a nerd as you can find. I wonder how far I can hack my own body?"
Pride again: "I already keep a hiker's first-aid kit in my pocket, and make other preparations for events that happen rarely. How stupid do I have to be not to put at least that much effort into making my everyday life easier?"
Does anyone have any experience in such self-motivation? Does this set of mental tricks seem like a sufficiently viable approach? Are there any other approaches that seem worth a shot?