Don't know why I couldn't have picked living in a place with year-round good weather, chose to install a supercharger, picked a career that provides tenure, or even bought a white Miata. Instead I chose to leave the oil filler cap off after changing the oil on the '97 last weekend.
I drove it for the first time this morning and was distraught to see smoke billowing from under the hood while stuck in rush hour traffic. I am fortunate the Miata's valve cover is a perfect shape to retain the loose cap under most driving conditions. Screwed it back on, wiped oil off of everything and all is OK. Wiped oil off of everything again. Plan to wipe oil off of everything again tomorrow.
I just feel better knowing a rocket scientist has done this very same stupid move.