It's rarely true.
You may be faced with the exact opposite problem—choice overload.1
Too many things to choose from blocking us without letting us continue.
Planning what you want to accomplish in the short- and long-term helps. It's like having someone telling you what you have to do, except that it's your past self instead of another person.
Capturing plenty of ideas when you are inspired to be used when nothing comes to mind also helps.
It isn't easy. But it's worth trying.