But you can't decline them or postpone indefinitely. It'll eventually force you to restart and update, and that's a problem.

When updates break a piece of critical software and can't be postponed indefinitely it's a real problem.

I've also run into instances where my PC was performing a task that required several weeks of processing time and Windows forced a restart because the process time was longer than the postponement window, so a task that's supposed to take 3 weeks suddenly takes 6 weeks.

Yes, security is important, but sometimes it's secondary to the entire fucking reason a computer has been deployed, and Microsoft shouldn't be dictating my priorities.