"I'd like to have my roof reshingled, but with glass tiles and it should be in the basement, and once you are half way I'll change my mind on everything and btw, I'm replacing your crew every three days".
Though the "I'm replacing your crew every three days" does cut a little too close the bone...
When I’ve engaged with a contractor for remodeling, I usually have some vague idea like “we should do something about this porch and deck and we’d like it to look nice.”
The contractor then talks to you about _requirements_, _options_, and _costs_. They then charges for architectural plans and the option to proceed with a budget and rough timeline.
Then they discover problems (perhaps “legacy construction”) and the scope creeps a bit.
And often the timeline slips by weeks or months for no discernible reason.
Which sounds exactly like a lot of software projects. But half of your house is torn up so you can’t easily cut scope.