Many time zones: You get to a new place and look up what time zone you're in.

Well, sorta

but it's no effort at all because my timekeeping device (phone) does this automatically.

For me, the time of day is internalized in a way that I think is hard to switch. Same as how I was raised with imperial units

even though I prefer (and use professionally) metric, the intuition can be a little harder to get. But to each their own of course :)