Time until delivery for good managers and customers is a range. Can you estimate getting 10kg of potatoes from grocery store that is 35m driving roundtrip away? Can you say it will be exactly 40mins because you can pick up and pay in 5 mins? I don't, I can say it will take between 40mins and 2h. There are always things like card terminal stops working or you get stuck in traffic because of an accident.
Complexity in that example is uncertainty like I do expect high traffic and there might be an accident happening but if there is less traffic and I hit all green lights 40mins going to be easy.
We all know bad managers and bad customers will expect me to get that bag of potatoes in 37 minutes and then ask 10x why did I not drove over that police officer that was stopping the traffic because of an accident to get their potatoes on time.
I don't follow how we go from "they are bad product managers and customers" to... therefor time estimates are bad. I do not think it is unreasonable for our primary stakeholders to ultimately care about time. I also do not think it is unreasonable to give error bars in estimates like "this project is uncertain, therefor estimates will be variable".
The bad managers are those who ask you for an estimate and then take it as a commitment.
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"How much time will this take?"
"Not sure; approximately 30 minutes, but could also be 20 or 40 minutes. If we are very lucky then 10 minutes, but if we are very unlucky, maybe an hour or more."
"Spare me the details, I just need one number for the report."
"Uhm, 40 minutes?"
"You just said that it would be approximately 30 minutes, didn't you?"
"Yeah, but I wanted to add some safety margin..."
"If we keep adding large safety margins to everything, then the project will take forever. As you said, some tasks are completed faster, some tasks are completed slower, on average it will cancel out. I need your best estimate."
"Uh, okay, then 30 minutes. On average."
...the next week...
"So, you guys told me this would take 30 minutes, but it actually took 35. I think we need to have a serious talk about your performance."
No, it's still a range, the difference is simply that a good manager would plan such that Christmas is at the very far end of the range. Bad managers will plan with the optimistic end of the range, and then expect crunch time from exploited workers following their passion.
Time until delivery for good managers and customers is a range. Can you estimate getting 10kg of potatoes from grocery store that is 35m driving roundtrip away? Can you say it will be exactly 40mins because you can pick up and pay in 5 mins? I don't, I can say it will take between 40mins and 2h. There are always things like card terminal stops working or you get stuck in traffic because of an accident.
Complexity in that example is uncertainty like I do expect high traffic and there might be an accident happening but if there is less traffic and I hit all green lights 40mins going to be easy.
We all know bad managers and bad customers will expect me to get that bag of potatoes in 37 minutes and then ask 10x why did I not drove over that police officer that was stopping the traffic because of an accident to get their potatoes on time.