Bad: Aliens who are bewildered by basic aspects of human society like cooking food and wearing clothes, implying that no similar practices exist anywhere else in the universe.
Good: Aliens who regard human society as largely unremarkable, but if questioned it rapidly becomes apparent that their understanding of the motive and purpose of various human cultural practices is subtly yet bizarrely askew.
“Ah, I see you have placed a simple lock upon the lavatory door for when you are… eliminating waste. I understand.”
“Thank you, Zazar…”
“You wish to make it harder for your enemies to ambush you during a moment of vulnerability. Very clever!”
“Wait, what?!”
“You wish to make sure that the parasitic lifeforms harbored in your intestines cannot escape without facing you in battle! How noble!”
“WHAT”