Manager: We (meaning you) need to do task A. How long will it take?
Me: Task A will take X days to do.
Manager: That seems awful long.
Me: How long do you think it should take?
Manager: It surely could not take any longer than Y days.
Me: Ok, it seems you have an answer to your question then.
Later:
Manager: It’s been Y days, why isn’t task A done yet?


Regardless of how effective it is at managing expectations, my reality is:
Mgt: We need A within Y days.
Stf: A will take X (>>Y) days, A/2 can be ready in Y days.
Mgt: O.K., give us A/2 in Y days.
Y/2 days elapses.
Mgt: In addition to A/2, please add B, C and D to the deliverable.
Stf: You realize, that’s going to take an extra 2X days to deliver.
Mgt: yes, but we absolutely need B. C and D, whatever it takes, as soon as possible, don’t waste time releasing A/2, bundle them all together for efficiency.
Stf: Coming up.
3X/2 days elapse.
Mgt: you know B, C, and D that we asked for? Actually, what we need are D, E and F.
Stf: well, we’ve finished A/2, B and half of C. When do you need D, E and F.
Mgt: ASAP, put C on the shelf.
X more days elapse.
Stf: here’s A/2, B and D, how do they look?
Mgt: You know, the full A would be better… but E and G are our absolute top priorities…