Why are software development task estimations regularly off by a factor of 2-3?
I have never found a better analogy to show the systematic difficulty in providing software estimates, which are frequently wrong:
Man, this is slow going! Sand, water, stairs, creeks, angry sea lions! We are walking at most 2 miles per hour, half as fast as we wanted. We can either start walking 20 hours per day, or we can push our friends out another week. OK, let's split the difference: we'll walk 12 hours per day and push our friends out til the following weekend. We call them and delay dinner until the following Sunday. They are a little peeved but say OK, we'll see you then.