Although not all your expectations are going to come to pass, you give yourself an infinitely better chance of succeeding by taking the proper steps. Regardless of your goal - losing weight, making more money, etc. - you can expect to achieve your goal if you plan and prepare for it.
You also need to understand that the path from where you are to where you want to be is not always smooth and straight. The reason for the twists and bumps is simple, and it has nothing to do with you.
It has more to do with the fact that not everyone is as interested in your success as you are. Some people may accidentally hinder your efforts; others who are in competition with you and have little or no integrity may try to sabotage your efforts.
Keep in mind, though, that when you hit those roadblocks or even reversals, your character, commitment, and attitude are the determining factors in your success. You need to carefully review your plan of action, seek wise counsel, and be particularly careful to feed your mind good information.
An optimistic, positive mind is far more likely to come up with creative solutions than a mind that dwells on setbacks and difficulties.
Success to you...