Yes, it's basically serendipity, and celebrating the thing in the moment. I stumbled across this plant in the park and fortunately I had my camera close at hand.
Flowers are tremendously expensive from the standpoint of water, which is often the limiting factor in hot, dry places. So a lot of cacti have short-lived and/or nocturnal blooms to compensate. Curiously though, they still flower in abundance, often synchrony, when they are doing well.
for the kind words and the acorns, people.