Calling In Sick vs Calling Out Sick

Having lived in six different states, from the west coast to the east coast, down south, and even in the Midwest, the colloquialisms, speech patterns, and dialects found across the country reflect the melting pot of our diverse nation. As a writer, picking up on these small language nuances fascinates me. For example, the same item can be known by many different names. What is a shopping cart in Oregon, is a carriage in Massachusetts, and a buggy in South Carolina. Similarly, do you get a drink from a drinking fountain? Or is it a water fountain? Or is it a bubbler? And don't get me started on sneakers verses tennis shoes! No material difference, the exact same thing, but very different names.
IN vs OUT
One of the smaller nuances I’ve recognized is how employees reference taking a sick day. For my west coast born and bred nature, I would say “I am calling in sick.” But here on the east coast, I more routinely hear that people are “calling out sick.” In verses out. Why the difference?
When I call “in” sick, I am calling “in” to the office to tell them that I am sick. On the opposite end, my neighbor will call “out” sick. She calls the office to tell them that she will be “out”, not at work and not present. She’s “out” of the office for the day.
So are you “calling in”, or are you “out sick”? Obviously, the rational and justification for both uses are correct. It comes down to where the emphasis is being placed. It is on the action, making the call. Or is it on the cause, being out sick.
Luckily, the English language allows for all our variety and personalities to be showcased in how we speak and write. Perhaps I’m the only one that notices small nuances like this. And there are plenty more I can reference. For example, how time and appointments are referenced. Do you have to be to work “at” 8:00? Or do you have to be to work “for” 8:00?
Am I alone? What language differences make your ears tingle when you hear them?