No particular quote to pull, but I just want to point out that a good chunk of Sartre's responses to critics begin with "actually."

It's a pity Sartre didn't live to see the rise of social media, he'd be the reigning king of "well, actually" comments everywhere. 

Most people who use the word would be rather embarrassed if they had to explain it, since, now that the word is all the rage, even the work of a musician or painter is being called existentialist. ... [By] this time the word has been so stretched and has taken on so broad a meaning, that it no longer means anything at all. ... [The] kind of people who are eager for scandal and flurry turn to this philosophy which in other respects does not at all serve their purposes in this sphere.

If Sartre wrote this book today, he probably be be accused of being a snobby gatekeeper. Or a mansplainer.

Someone recently told me of a lady who, when she let slip a vulgar word in a moment of irritation, excused herself by saying, "I guess I'm becoming an existentialist."

Seems like the correct use of existentialism to me, tbh.