For the last four years, I've worked hard to get rid of promises because making those promises has, in my experience, more side effects that positive impact.
I'm one of the people who in face of a deadline don't perform better. I get paralyzed. Knowing I have two hours to work on something that could be done in two hours but also could take four, I tend to not start. With free space ahead of me, I work productively and complete tasks. Thinking about how long is crippling to me. So many people assume I will answer those questions, so over the years I've learned ways of managing my contributions in ways that suit me.
I've worked with a lot of people who in face of a deadline use significant time on making excuses or covering their backs. "You did not tell me of this requirement", "I was sick for three days", "the dependencies were more complicated that I thought". All of these are true, but the more individuals commit to deliveries, the more they also commit to making sure they're safe.
I work to change my world to daily (or more frequent) releases, so that we can plan (and get surprised) with an item at a time. I work from the premise of trusting that we'd rather do good things and make an impact in the world we're contributing to. I don't want to be one of the people who on a personal level carries the responsibility of all surprises just magically adding hours to work days, I would rather be one of the people who delivers value all the way to production fast trusting there's always another day to do more.
Two week sprints, sprint commitments under uncertainty and all the clarification ceremonies and blame assignment when commitments fail seem like such a waste of smart people's potential.
Some of us quietly invest in the ceremonies others want. Others work to change the ceremonies to focus more on value.
I'm so happy that the big deadline up front has moved to a small deadline close by. It's better for the company but it's definitely better for me. The stress of artificial deadlines can be all consuming.