Sure. I'm not arguing for flat-earth, but I've never called someone to check if the sun has set for the purpose of satisfying my curiosity about the shape of the Earth. It is, however, implied in the conversations we have every day (coworkers finishing work at different times because of timezones) so there is no need to ask some things I guess.

My point was more that we take a lot for granted, some things obvious, some maybe less so, and it is not always silly to question even the simplest of assumptions.