Paul Dawson at Fluxx shares a great example of a constraints-driven exercise he calls "time boxing" to deliver a lesson on the power of constraints. After asking people to draw a cat in only 15 seconds -- he finds that their rushed drawings are all still pretty recognizable as a cat (my 15-second attempt is above).
He suggests that giving people a shorter amount of time doesn't make them draw something different, they just draw the same thing, only more elaborately:
Try time-boxing tasks (and particularly discussions) that seem hard, or decisions that take too long, and see what happens. You will almost certainly get as far as you need to in whatever time-box you allocate, and it will help you sift out what is important, and what is not.
Next time you're trying to get to the essence of something with your team, make sure you ask yourself if you really need more discussion time to make it perfect, or if you'll get the same insights from your minimally viable cat in a fraction of the time.