I guess it has to do with your work ethics and the values you hold important--this may be a result of your growing up so I'm not sure it's an easy thing to change, because really it's how you see the world. On the other hand, there could be defining events in your life that would completely change your outlook, redefining what you consider important. I think this works chiefly at the subsconscious level--i.e. it's not something over which we have cognitive control: it controls us.
External vs. Internal Driven People
Some people, presumably such as you, get a lot of motivation from external stimuli, like how others perceive you, a sense of obeying authority, workplace pressure, or competition. These have always struck me as inconceivable, since I'm entirely motivated by internal stimuli. I sometimes find it hard to convince myself it's worthwhile to go to college or work, because the stimuli there are mostly external and they actually demotivate me. On the other hand, I get extremely motivated following my own at-home study plans, workout routines and personal side-projects.
Having realized this, it also strikes me as interesting how productivity advice should really be broadly grouped into either external driven or internal driven--yet most articles fail to notice this difference and offer end-all be-all methods as if everyone was to get the same out of them. For some, some article's method may work brilliantly, for others it might do the opposite, effectively passing for bad advice. Several times I find myself scoffing at ludicrous advice given online--until I remind myself that for some people it's pure gold!
Life 101 for The Internal Driven
The way around for me in my day job was finding a company which gives me autonomy and leaves me to my own devices--so I'm amazingly motivated to bootstrap myself and get better at what I do. It has worked perfectly. If they had pressured me daily on my tasks, or laid out my work for me with little room for flexibility, I'd have been utterly demotivated, so it would have been counterproductive for me.
For college, I'm yet to make it work my way towards my degree, so I'm increasingly inclined to drop out and continue my (life-long) education through books and MOOCs--Massively Open Online Courses such as Coursera and Khanacademy's.
Manufacturing An External Stimulus
Coming from the other side, you should probably find ways to tack external stimuli onto your personal goals: find peers who can share the goal or watch your progress (e.g. for exercising there's Fitocracy and Fleetly), do the work or exercises in a social environment where others can see what you're doing and put pressure on you, or go all out and quadruple your productivity by hiring someone to slap you when you stray away!
These tricks and devices are not silly in the least, you have to use whatever you can to motivate yourself through whatever makes you tick. Motivation is a wonderful yet fleeting state of mind, and most people understand little enough about themselves that they leave whole areas of their life lacking (such as private goals for external-driven people), so you would be way ahead of most people by finding how to make yourself perform consistently in all areas of your life. It might be you have just been trying it the wrong way for yourself.