Lights

Our stateroom on the ship was an Interior room (translation: no balcony,no windows).
This means that our room gets incredibly dark without the use of lights.
Luckily, there are lights everywhere. The bathroom, vanity, foyer, and each of the beds has its own light, so you're never much further than arms reach from a switch.

I like to sleep with all the lights off. This is a problem. My mom likes to sleep with the lights on. Lucky for me, she falls asleep quickly. After she's been asleep for a while, I turn the lights off, and drift off to dreamland.

I forgot that she always wakes up in the middle of the night to use the restroom.

I woke up to her yelling at me for turning off all of the lights.

"Did YOU turn the lights off? DON'T DO THAT! It was so dark, that when I opened my eyes, I panicked. I THOUGHT I WAS BLIND!!!"

We slept with the lights on for the rest of the trip.