They mentally convert the points to some "X days" and then beat you in the
head with it.
That's actually why I really dislike Fibonacci estimation. If we just estimated days or hours, then I could say, "Okay, this is going to take me until Wednesday," my manager would reply with, "Wednesday? It's going to take that long?" and then we could have a discussion about why it's going to take so long. Or, worst case, manager says, "quanticle, I really need this to be done by Tuesday," and I know I'm going to be staying late until it's done.But with Fibonacci numbers, it's like, I estimate a 3, manager nods and agrees that this task is a 3, and then it turns out that when I said 3, I meant that it'd take until Wednesday, but manager thought that a 3 point task would be done by Tuesday, and now manager is mad at me, and I don't know why.
The old way sucked, but at least it sucked in an up-front and transparent way.