Towards the end of every year I work on my list on intentions. I do this no matter what and I work on those lists all year because, well, I just don’t want to be the kind of person with a larger list of regrets than accomplishments. 
I know that over the next year, one of the things I was going to put on my list was “read all the classics.” The more that I thought about that though, the more difficult it became to figure out WHAT DOES THAT EVEN MEAN? What makes something a classic? Is it the time that has passed in direct ratio to it being considered influential? You can break it up into time periods: Pre-Civil War, Industrial Age, Antiquities, Vintage, Contemporary, Romantic, Greek, and on and on and on. Is it if it became popular? Or banned? What about great YA or Sci-Fi?
See what I mean? OVERWHELMING.
If you over think it, you can even be genre specific. For example, a classic horror novel would be The Shining or Carrie, wouldn’t you agree? Actually, you could do an entire list on Stephen King! 
What would be on your list of classic books?
There is a great Tumblr called Teaching Literacy and if you aren’t following it you should be. They had great suggestions and a link to a starter list that you should check out.
But what if you are a book person?
My biggest issue is most of what people would recommend, I have already read. I was lucky to have teachers for grandparents so a love of books was instilled early. Growing up overseas, I got to visit so many inspirational places that many writers frequented all over Europe. There is nothing like going to Stratford-Upon-Avon to study Shakespeare or reading The Prince before visiting Florence, Italy.
I am very, very lucky.
But I know there are things I have missed. While I have only finished sections of it, one of my first to finish this month is The Art of War. There are a number of political theory books I want to revisit and Shakespeare plays I want to go through. I am thinking of going back through Rice’s Lestat series and then move on to more traditional things I may have missed. When you have read most Steinbeck by the age of 13, it’s hard to find things to put on the list. No matter how hard I try, most of what has ever been on Oprah’s lists, I just don’t care for. Same for the Nobel Prizes…just didn’t love The Goldfinch the way I hoped I would.
So tell me, what is on your list? What is a book you continue to recommend to people? Has it changed, as you have gotten older? My tastes have always been crazy eclectic. If you like horror, I again and again recommend The Historian. I devoured that book.
In case you are interested, here are a couple of lists I found. Enjoy!
25 American Classic Books to Read
100 novels everyone should read
30 Books you should read before you’re 30
Queen of the Universe 
Quite curious that you read so much Steinbeck, I had such an easy entry with The Red Pony and I hated it. I can’t believe I could have stomached The Grapes of Wrath at that age, seeing as it’s not something I’d read nowadays either. As for what Classics are, I stick to the recommendations of the Penguin publishing house, they offer such a broad variety you can’t go wrong much.
It was mostly because my dad was a fan and they were available. I love Of Mice and Men and also Cannery Row. I wasn’t a fan of The Red Pony either! I enjoyed Steinbeck but hate Faulkner so much and he is constantly put up as a “great writer” despite much of it being in comprehensive. Light in August was required reading in high school when I was a senior and I thought it was a poor choice for that age altogether. Maybe I would have like it when I was older, I don’t know but it kept me from reading anymore of his work.