It is Smarter to *Over* Promise & *Under* Deliver - find out when & why 

I 100% support the underlying idea. For personal projects, I set the timeline using this. But in professional life, I have seen it backfire with one very outlying scenario - Internal tram starts over promising. They start delivering on time also. But sometimes, the fact that the bottom most food chain engineers overworked to meet this deadline, and that gets accidentally overlooked. But for tech lead, we have been meeting targets so, maybe the next delivery timeline is also going to be framed similarly. Now, I understand, it is something employees can bring in the 1-on-1s, and resolve there. But at the same time, I think having a mix of "over promising" and "under promising" projects depending on the business values they bring, could be a tiny bit better. Just thinking aloud in the space you offered.

The core idea is very valuable, as almost always the case with Shreyas. But I believe there's a catch about definitions here. You give promises to those "outside" (client, manager, board, public etc) even if they are part of the same organization. Unmet promises have consequences, which drives us to lower the expectations. But in this case, you actually define a delivery target for yourself (or a core team that is inseperable from you) , which in my estimation does not count as a "promise". It's more of an appetite, as the ShapeUp people call it.

Although I agree, this can only be done at certain companies (or certain startups). I could see folks with heavy optics driven experience having a tough time with this long term.