I'm on a project that started with a deadline before we really even knew what we were building (months away from that deadline and we still don't). Despite seemly unlimited budget to throw at it, technical debt is out of control and we're already moving slow.
I get pulled into 8 hour meetings every other week where 30+ people try to "plan" our way into building faster.
There are countless challenges with this project, but the forced timeline is by far the worst of it.