I agree, if we're talking about books. Further, I agree that some people are way better at making good quotes than others.

But even a broken clock is right twice a day-- and if someone has taken the trouble to excerpt a quote from an author (i.e., they have pre-filtered it for me), it does not take me significantly more time to read the quote than it does to verify that I like the originator. (Unless I know I'm unlikely to agree with the aesthetics of the person who made the excerpt, but that's a different story entirely!)