But most everyday tasks don't need a deadline

I think that's the crux of our disagreement. I think most everyday tasks do indeed have a deadline. Even if that task specifically doesn't have a deadline, it's often in service of a broader task which does. The premise that all agile methodologies are built on is that customers are going to be more willing to drop features rather than add days to the schedule. I think experimental evidence has proven that premise false.

And frankly, it was kind of a ridiculous premise to begin with. Can you imagine if other professions adopted "agile" methodologies? Can you imagine your auto mechanic telling you, "Okay, well, putting the dashboard back on is going to take me until tomorrow, actually, but, if I only attach half the bolts and leave the speedometer disconnected, I can get it to you by the end of the day. Would that be all right?" Or a home-builder saying, "Okay, well, the drain pipes are proving trickier than anticipated to install, but I can give you the bathroom without the drain pipes, and install those in the "version 2.0" release. Would that be okay?"