Do you give artistic credit to any photo/art you have ever taken a screenshot of that wasn’t your own? I would think it’s the same idea.

Maybe if you put the quotes between “quotes”.
It’s still clean, and it is also clear that you quote somebody.

Legal, probably. Ethically – no. If you’re reproducing someone’s work and passing it of as your creation – well, that’s borderline dishonest.

What are you using them for?

You won’t be arrested. But if yo make any money at all from it, even just a nickel, you can be sued and have to pay damages.

and like @elbanditoroso said, it is very dishonest. People who do that and get caught are openly ridiculed and deserve it.

It’s not clear why you want to do it?

Exactly. If it’s just for random social conversation it’s not as important as is if it’s for academics. But it is still a question of morality if you try to pass it off as your own, even casually.

I would be livid if you stole my academic work without attribution to make your social media page look “cleaner”. It is theft.

Edited to add: Rachel Hollis just got some backlash for using quotes without attribution. https://www.buzzfeednews.com/article/stephaniemcneal/rachel-hollis-girl-wash-face-accused-plagiarizing-quotes