There are reasons that tight deadlines and huge pressure often get results.
The first is that people get immediately more pragmatic about what the actual requirements are, and agree to do less. Less can be done more quickly, and completed items are less likely to be subjected to a full loop of subjective tinkering.
The second is that when faced with a deadline, and some pressure to achieve it, people focus on just the single most important task.
The single most important thing to do right now is abundantly clear in these high pressure situations.
In many teams, and in most software teams, that single most important thing is often lacking.
Meetings, emails, taps on the shoulder, emergencies, can-u-justs. They all fog the clarity required to get that next thing done.
Add to that the general lack of team or project deadline, deadlines which are set more than a couple of days away, tasks which are large and poorly defined and cannot be completed within a couple of days, and you make the right thing to do right now a choice rather than a certainty.
Setting small achievable tasks which are attached to short deadlines will get a team doing less, but creating more value. Even if that’s within the container of a project, release, sprint or phase.
As a nice side effect, it will also lead to feelings of progress and success for those involved.