Mine have worked flawlessly 100% of the time... but my sample size is 100.

Have you absolutely determined there are no power supply glitches ? I would say that any glitch on the power supply, no matter how narrow, any glitch getting to pin 1, and any missed watchdog causing a reset is valid.

I have seen a strange problem on the PB reset pin, where a glitch on PB reset, while trying to keep the part in reset, allowed it to go out of reset. This may have been the maxim version, though.