I was listening to the Liftoff podcast episode about the Voyager missions. They pointed out that it launched in 1977 - well, NASA put it best:

This layout of Jupiter, Saturn, Uranus and Neptune, which occurs about every 175 years, allows a spacecraft on a particular flight path to swing from one planet to the next without the need for large onboard propulsion systems.

That's a hard deadline. "If your code isn't bug-free by August 20, we'll have to wait 175 years for the next chance." No pressure.

In startups, I often hear of "hard" deadlines like "we have to ship by Friday so we can keep on schedule." Or worse, "we promised the customer we'd have this by next Tuesday." To meet these deadlines, managers and teams will push hard. Engineers will work longer hours in crunch mode. Code reviews will be lenient. Testing may suffer. New code might be crammed into existing architecture because it's faster that way, in the short term. Coders will burn out.

These are not deadlines, they're bullshit. Companies are generally not staring down a literal once-a-century event which, if missed, will wind down the entire venture.

If you're consistently rushed and not writing your best code, you're not learning and improving. The company is getting a crappier codebase that will slow down and demoralize the team, and engineers are stagnating. Demand a reason for rush deadlines, and don't accept "...well, because the sprint's almost over..."