Imagine you wake up one morning and find an alien life-form in your closet. You immediately befriend this being and don't want it to be taken away. Luckily, the life-form is able to mimic human behavior and language but does not understand the unwritten cultural rules that we follow naturally. What shifting cultural norms, practices, behaviors, language patterns, etc. must it be able to navigate on a daily basis?

Basically, I just want to see some others' opinions on what some unwritten cultural rules are in society. Any help is greatly appreciated!

When you make eye contact within a certain distance, express a greeting.