So I believe you are wrong on thinking it is unnecessary stress, based upon some research done by Dan Ariely on students getting their work done with and without deadlines. You have to read his book Predictably Irrational for the full story, but here's a synopsis: http://danariely.com/2010/08/30/back-to-school-2/
Long story short is that without deadlines people tend to push off work to the latest possible moment, at which point they tend not to be able to do as much as they thought they could in that short time space, so it actually causes more stresses on them than it would have to have had a series of deadlines along the way.
Interesting thoughts on procrastination. Comparing a software developer that has passion for his craft with some high school student is probably not the right approach though either...
College students actually. And I'd agree somewhat, although I'd say you could easily extrapolate it to newly hired developers fresh out of college, and that it may be extensible beyond that. Either way, research points against your conclusion and you have no factual basis for it, so it'd be good to find some support.
Edit: Here's some more research which backs up why your conclusion may not be correct: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3374478/ Granted it is probably too early in the research of this area to say your conclusions are wrong, just that the research is leaning that way
That research lines up pretty well with my own experience in college. It haunted me until my 3rd year when I was so bogged down with advanced projects that I just couldn't keep procrastinating because I was only barely getting the minimum done I needed to in the last hours I had before the projects were due.
Professionally, I've learned my lesson and while I've had some moments of procrastination (especially for tasks that I have little to no motivation for), I tend to work more steadily than I did in those first few years of college and I rarely run up against a deadline (soft or hard).
However, I've worked with plenty of software developers who wait until the last perceived moment and work crazy hours to try to meet the deadline. I'm not sure what they would do if they didn't have that deadline. I suppose they would either get fired for lack of productivity or just be productive enough when nudged to keep their jobs.
Long story short is that without deadlines people tend to push off work to the latest possible moment, at which point they tend not to be able to do as much as they thought they could in that short time space, so it actually causes more stresses on them than it would have to have had a series of deadlines along the way.