Fritz Leiber

“ Just then, there was a loud splashing in the bathroom. The Professor's family looked toward the door. The splashing stopped and they heard the Martian moving around. Then the door opened and the Martian appeared in the Professor's gray pin-stripe suit. His mouth curled sharply downward in a broad alien smile as he saw the Professor.
"Good morning!" the Martian said happily. "I never slept better in my life, even in my own little wet bed back on Mars." ”

“ The Martian's mouth curled happily downward and he said, "Thank you very much," and was off.
Comprehension burst on the Professor. He caught up with his guest at the foot of the stairs.
"Here, I'll show you the way," he said.
"No, I can find it myself, thank you," the Martian assured him.
Something rather final in the Martian's tone made the Professor desist, and after watching his visitor sway up the stairs with an almost hypnotic softly jogging movement, he rejoined his wife in the study, saying wonderingly, "Who'd have thought it, by George! Function taboos as strict as our own!" ”

“ No one but ourselves knows that the Martian is on Earth, or has even the slightest inkling that interplanetary travel has been achieved. Whatever we do, it will have to be on our own. But to break in on a creature engaged in—well, we don't know what primal private activity—is against all anthropological practice. ”