Haha!
I remember calling abroad a couple of years ago. Exactly the moment I greeted "Good afternoon" I remembered the time difference and corrected myself: "ehh. correction, good morning!".
I was replied with a couple of seconds of akward silence and a "yes, it is morning, sir."
Another thing is readback. I have several times asked waiters, bank employees, etc for readbacks.
Readbacks are actually quite handy!