Ok. In my case, I didn't want to try because I was afraid of failure. I know how stupid that is because not trying in itself is failing.
That's quite common in actuality. Obviously this is an extremely complex subject. I've spent most of my life researching fitness and nutrition and I feel like I have a pretty good grasp on those subjects.
I've spent an equal time on human behavior and I'm nowhere near as well versed in that area. It's just so dynamic and individual.
That said though, I like to keep things simple and break them down into usable thoughts. Like pain and pleasure; I've used this thought process quite a bit in some of my posts in here.
We all act based on two things: 1) The need to avoid pain and 2) The desire to gain pleasure.
And this very real and understandable concept, simple as it seems, is quite powerful. In many situations it isn't cut and dry. For instance, in some cases it's a matter of choosing between the lesser of two evils (pains). But the fact is these two forces dictate a vast majority of our choices, regardless of whether or not we're conscious of it or not.
To 'grab hold' of the concept consciously and really do some digging and rearranging internally can make all the difference in the world in terms of someone succeeding or not.
This concept is closely related to perception; we all know how perception is our own reality. Perception can make or break someone dead in their tracks.
Without rambling on too much, which I may have done already, your particular case is common in that many people never put enough thought into something they want to accomplish, they never take that (what seems to be a giant) step into progression toward their desires. They avoid doing so b/c of their fear of pain. They don't want to fail. They're afraid of the unknown. What if I succeed yet I'm still unhappy? Maybe it's a matter of having to find yourself a new identity. Some people are too concerned about what others will think if they embark on a journey such as this. For others it's a case of admitting they were wrong all along and the pain of owning up to that idea and actually having to change because of it is too great.
I could go on and on.
But the fact remains the pain you have associated with conquering your desires far outweighs the pleasure you think said desires will bring. More notably, that pleasure that you know the obtainment of your goals/desires will bestow aren't as real as the pain you have linked to the change.
I've used this philosophy with quite a few of my clients to 'enlighten' them. I find it's a good way to help people think about what they're thinking about. It's a small tool... one of many.
Once these sorts of associations are identified, you can begin tweaking your perceptions. You can consciously link a ton of pleasure to that which you want and a ton of pain to that which you don't want. There all sorts of rituals, habits, tasks, etc that help solidify these new links, and once solidified, the choices you had trouble making before become a whole lot easier.
In a nutshell, it's a matter of redirecting your focus. What you focus on most is what you'll get. That's such a powerful concept that I've found to be so true.
I'll stop now but thought it a worthy thread to yap a bit on this subject.