Growth comes from doing it when you're not motivated
The payoff of Systems are better than goals is the exponential growth of habits. 1% better every day means 37 times better in a year.
When you start a new habit, you're going to be excited, see quick progress, and feel motivated. But then you will get bored.
Progress will slow down, you'll realize that just like everything else this habit is not a silver bullet to your entire life. And this is where the real opportunity is. Are you going to continue despite your lack of motivation, despite your boredom? That will be the difference between you and the rest.
It feels meaningful and exciting to go to the gym on January 1st, and it doesn't feel so important on June 1st. Going on January 1st says "I'm a person who wants to work out", while Going on June 1st says "I'm a person who works out". (Identity change is necessary for long-term behavior change)
No single workout is going to change your body or your life though, it's the consistency that will produce results, so it's pushing through those times when you're unmotivated that you're taking the most important actions.
Anyway, Motivation comes from Action
TLDR
Motivation is overrated. When you're motivated it means it was already what you wanted to do. You can only grow by doing things you don't want to do already — when you're unmotivated.
References:
Motion vs. Action (really @ing me)
"The difference between getting things done, and preparing to get things done. A method of putting off the chance of failure into the future.
You want to practice instead of plan - get your reps in"
As Machiavelli noted, “Men desire novelty to such an extent that those who are doing well wish for a change as much as those who are doing badly.”
Now is the perfect time to start: "Professionals stick to the schedule; amateurs let life get in the way. Professionals know what is important to them and work toward it with purpose; amateurs get pulled off course by the urgencies of life."