Time And Creativity

If not for deadlines I would rarely finish anything, so I fully understand the need for time limits.  However, I do question how it is possible to be creative with time constraints.  Normally (for me) inspiration comes first and then I begin work, but what happens when there's a date circled on the calendar and inspiration doesn't come?  Panic sets in and fabric starts flying regardless of an idea or plan!  Now the question is...can art really come out of panic and lack of a plan?