I hate deadlines simply because organizations I have worked in tend to assign them indiscriminately without any reference to reality. Upper management wants to set a deadline for a big project? Then they need to be prepared to commit and compromise. While developers continuously deliver, product owners and stakeholders need to continuously review, reevaluate, and adapt.

In Thinking Fast and Slow, Daniel Kahneman offers my favorite object lesson on the topic:

http://txti.es/kahneman-outside-view

He sums up:

This embarrassing episode remains one of the most instructive experiences of my professional life. I eventually learned three lessons from it. The first was immediately apparent: I had stumbled onto a distinction between two profoundly different approaches to forecasting, which Amos and I later labeled the inside view and the outside view. The second lesson was that our initial forecasts of about two years for the completion of the project exhibited a planning fallacy. Our estimates were closer to a best-case scenario than to a realistic assessment. I was slower to accept the third lesson, which I call irrational perseverance: the folly we displayed that day in failing to abandon the project. Facing a choice, we gave up rationality rather than give up the enterprise.

The suggestion that the enterprise should have been abandoned all together can be misinterpreted as fatalistic, even nihilistic. I take it to mean that you've got to do your research (the outside view), rigorously define your MVP, and then work from there. If your deadline is fixed, be ready to scale back.

His distinction between the inside and outside view is the key. For a project to have any hope of realistic timelines, it needs to be understood and the outside view needs to be applied.