When it comes to short stories, it's hard to write something that really leaves a mark. The shorter the story, the harder it gets. Actually, I can only think of two.
The first one is "Sentinel" by Fredrick Brown. I read it when I was 9 and it struck me like a lightning, igniting a passion for sci-fi that is still with me decades later.
The second one is "The egg" by Andy Weir. And it's even shorter than the first one.