You got me. I should have specified that a certain threshold of day-night length difference would have to be exceeded to be subject to celebration. I'm glad I

You got me. I should have specified that a certain threshold of day-night length difference would have to be exceeded to be subject to celebration. I'm glad I specified the planet, or else someone would have pointed out planets without a tilted axis. [Edit] Fair point, though. I asked for a single counterexample and you delivered.