I thought curiosity killed the cat.
I mentioned a failed cat that I experienced above. The dealer service manager at the dealer thought that a failed ignition module that I had experienced a few months earlier which turned my 4-cylinder into a 2-cylinder on Christmas day the previous year may have lead to my premature cat failure.
As I loaded the family into the car on Christmas day to go visit relatives, the car ran extremely rough, so I parked it and we all jumped into my son's Scion to go visit family. I can tell you that 6'1" does not fit well in the back of a tC.
Anyway, the next day I dropped my "2-cylinder" off at the dealer (1 mile from the house) to get it fixed under warranty. It was, as I suspected, the ignition module. It was dumping raw fuel into the exhaust for only about the 5 or 10 minutes it took to get to the dealer. But the following March, the cat failed.