How to get things done?

How is it that when life is busy and full, I get a lot done, but when the diary is empty and family not around, I just faff about, getting nothing done?
I am really good at meeting deadlines, but if there is no deadline, I procrastinate, until a task drops off my To Do list,
I know in one sense it doesn’t matter, there is no rush, but there ARE things that need doing.