From the Guardian:
First, “lexical directiveness”: memorable quotes are built from simple sentences, constructed in the normal way (or with “common syntactic patterns” as the linguists call it). But, the memorable phrases that we use are unexpected in those unsurprising sentence constructions.
Their second finding was that memorable quotes tend to be more generally applicable, and aren’t tied to the particular area in which they were first developed. Even better, they found strong evidence that these principles apply to non-movie lines, such as advertising slogans and brand language.