Hasn't anyone tried to replace time estimates with probabilities?
(Like "There's a 80% chance we'll finish this today." )
You immediately start to understand why it can take so much longer than expected (You've rolled a dice before; I want a six... How long will it take)
I don't know if I am supposed to roll a 20 on a D20 or a 8 on a D8 to begin with.
Time estimation on a macro or micro level is just educated feelings.
The thing I notice with people that are forced to estimate time and have nagging managers is that they start to report time according to how much the task was estimated to, to make the burndown chart nice.
I.e. if one task is finished early a late running one gets the hours giving the illusion of getting better at estimating. I think Joel's estimation method for Frogbugz had the same fate linked in somewhere above.
(Like "There's a 80% chance we'll finish this today." ) You immediately start to understand why it can take so much longer than expected (You've rolled a dice before; I want a six... How long will it take)