In my family, there was one cardinal priority - education. College was not an option; it was mandatory. So even though we didn't have a lot of money, we made it work. I signed up for financial aid, Pell Grants, work study, anything I could.
I committed a cardinal sin as a kid. I never spoke, and my mother thought there was something seriously wrong with me. A silent child is regarded as a problem in Ireland, and I just read all the time.
If any sort of error is inexcusable, it's an incorrect phone number. One of the cardinal rules of copy editing is that every phone number published must be checked.
When the depressive psychosis has become manifest, its cardinal feature seems to be a mental inhibition which renders a rapport between the patient and the external world more difficult.