Do we have any red port wine left?

Honestly, yeah. That's what I relied on as well and what was taught to me. Also what I then taught to the people under me. I have no other real way of understanding it. I know why we use port/starboard but I've never looked into why port/starboard are the words we've stuck with.

My grandfather was a bomber pilot and he always remembered it by picturing himself flying north along the east coast, where all the ports would be on the left.

That's essentially how I always remember it. Port and left both have 4 letters.

Also, the old name for "port" is "larboard", which starts with an L for left.

Additionally, "starboard" has 'r's (for "right").

and even, as in even numbers.

Port, left, even...all words an even number of letters Starboard, right, odd...all words are an odd number of letters.

Port is short. My BIL taught me that this summer!

Okay that's infuriatingly clever... I'm going to have to use that.

And port is red. Green means you're on Starboard and GET THE HELL OUT OF MY WAY!!

Left and Right rely on the orientation of the person. So if I'm looking ahead at you, and you're looking at me, my left is different than yours. However, port and starboard don't change based on position of the viewer but the position of the vessel. Cuts out any ambiguity.

Left and right are referenced to yourself, or relative. Port and starboard are referenced to the ship, or absolute.
It's the same reason people who work in theater say "stage right" and "stage left" instead of just "right" and "left."
Imagine being on a boat for weeks, in the middle of the ocean, with no land in sight; it makes a lot of sense that you would think of locations in terms of the ship, as that is your only reference point.

Historically, boats had rudders (or “steer boards”) along the side of the ship instead of in the middle like we’d see them today. It was always on the right side of the boat, so to avoid smashing your rudder into the dock, you’d dock your ship on the other side. That means it was always the left side that literally faced the port, while starboard faced out into open water to protect that side from damage.

Then you have to say something like "your left or mine?" This removes any ambiguity, and that might matter when one is at sea.

Also, port is red and Starboard is green. Usually boats will colour the sheets to match. It helps to identify the lines when someone tells you to ease the port sheet.

Because left and right can be interpreted as direction from your point of view. Port and starboard are always understood as left and right of the vessel you are currently in.

Port and left have four letters.

Mars also has 4 letters, which is useful when you're trying to remember which portal to travel through at the end of the Vault of Glass raid.

Your pointer finger and thumb make an L on your left hand.

Yes.

But the red on your boat is always port.

Nah, but we did live on an island where sailing and fishing is very important. Our boat was trash but we did have a boat.