If you google the word "habit" you'll come across this definition: "a settled or regular tendency or practice, especially one that is hard to give up." Many will see this differently than others, but to me it represents the separation of those who work towards the goal at hand, while for others they're afraid of consistency or find out how hard one must work to "get there".
One should approach their physical goals as much as school or work, you prioritize it as part of your work or school day. In all of my years in this industry, this is where I've seen my clients at their most success. They get to the gym, work their butt off, leave, and make sure they stay on track with their nutrition throughout the day, only to do the same routine the next day, 4-5 times out of the week. To some it may sound boring, but when you see the results come along it will change your thought process.
Sometimes "breaking" the routine can be detrimental. It can be as bad as skipping a workout, or missing a meal during the day. Something so little can throw you back, trust me. Let's be frank; life happens. Stresses may change priorities, or an emergency can derail plans for the day. The best advice I can give; reschedule your workouts or get back on track the following day if a situation can be overwhelming. I've been lucky enough to prioritize my routine high without much distractions.
But of course many will say "it's your job", but I beg to differ. I have goals for myself as much as the next man, the only difference is I know the sacrifices made to achieve them. I practice what I preach because my success comes from the habits I make, day to day. Do the same & you'll see the fruits of your hard labor.