This is an actual conversation I had with one of my old bosses.
Boss – How long will it take you to learn this new software?
Me – I don’t know. How long do I have?
Boss – It doesn’t work that way. Tell me how long you need.
Me – Hmmm, a week.
Boss – Can you do it in three days?
I, of course, said yes, but I should have said, “Did we really need to have this conversation? Couldn’t you have just told me I had three days to learn the new software?”