Comment by fgdelcueto

When progress bars are not useful it is because the underlying problem is hard to extrapolate faithfully. If you are doing just a few tasks where each one takes a significant different time to execute, it will be hard to estimate. More often than not, they work fine, IMO. When they don't, it is because for that particular problem it is genuinely hard to do. It isn't programmer's laziness, I think, in most cases.