Essential Short Story Readings?

Hey everyone, I recently got back into reading/writing.

I used to read a ton when I was younger, but I seriously didn't read at all for years, and have only started again the past couple years. I find I really struggle with reading longer novels, as I get bored and put it down for too long – I have been reading the Hobbit on and off for 2 years, even though it would only take me a week realistically to read it. I've only read one 600+ page book in the past decade.

However, I've found I do get through shorter stories, as they hold my attention long enough to finish. I've recently read EAPs 'The Raven', and 'The Tell Tale Heart', but these are incredibly short. I also read 'The Old Man and The Sea' a while back and thoroughly enjoyed that.

I'd like to read some more short stories, as I am now about 25% of the way through my first rough draft novella, and feel the personal need to read more as I progress through it.

What would you consider essential short stories to read?? I'd love to work through a list of the best short story recommendations. Thanks!