All well said.

But the real test of a top-notch businessman is someone who will correct
his foul-ups even at his own expense. Are you professional enough to take
a financial loss on a job, in order to keep your end of the bargain? Most
contractors seem to have an inflexible idea that they must make money on
every single job. When things go wrong, they just default while they're
still ahead.

What about something that the customer won't know was a problem, a hidden
defect you can cover up, like too much water or too much time in the
concrete mix? Do you do it over at your expense?