[hipsterrific]

It's debt for the same reason that when you keep borrowing money, things just pile up and you feel overwhelmed. While no one will repo my car for not following through on an idea, it also means that the things in my "want to do" list grows and it becomes apparent that I'm stressing myself over what to do, which to do, when to do, etc. It's the same as taking on too much monetary debt; you feel overwhelmed and your limited resource starts to spread thinner and thinner. Same with idea debt; your time (resource) is spread thinner and thinner.