The hard part is justifying the time spent on a project. You often start a project and feel like it's not the best use of your time. That you may be the only one to use the project or find value in the project and that's enough to kill motivation. Why start a business if the vast majority of businesses fail? Why start a business when there is already so much competition? Why write a novel when there is no hope of selling it? Then there are the "I'm too old for..." thoughts.
These thoughts eat away at people.
If someone pointed me to my purpose project and told me if I were to keep at it that I would find guaranteed success, then I would have an infinite well of energy at my disposal. But of course, no one is there to tell you that.
I think the pbjective of a project is to...be a time filler, like I can definitely watch Netflix and then Netflix does not satisfy my creative mind so programming something would be a better exercise.
Start doing things is easy, too.
Finishing stuff, is hard.
The trick is to gradually work your way up from small, completed projects. If you start big, you probably fail big.