A little learning is a dangerous thing; Drink deep, or taste not the Pierian spring.
-- Alexander Pope: Essay on Criticism

Pope means that too little learning will leave us thirsty, presuming we have any clue whatsoever.

Wrong: Those who fail to learn the lessons of history are doomed to repeat its mistakes. For Example . . .

Actual: Those who cannot remember the past are condemned to repeat it.
-- George Santayana: "Reason in Common Sense". An unlikely example.

It was only while looking these items up that I learned I was on the wrong side of this. The notion that history can "repeat" itself is, in the strictest sense, nonsense. When humans live in harmony with nature's rythms, history can be cyclical, and thus repeat. But that hasn't been the case for a very long time.

Judgements about history can and do repeat, however. The reason I always gave Santayana credit for the clarified quote is that it's our perception of the meaning of history that's important, not the details.

It should be noted that failing to learn something is a far cry from being unable to remember it. It seems to me that Santayana is saying more about a deliberate or inculcated ignorance, rather than a stubborn resistance to learning.

In any case, with both anmesia and ignorance running amok, it's silly to split hairs.

And of course these simple misquotes result in radically altered meanings . . .

Wrong: Money is the root of all evil.

Actual: The love of money is the root of all evil.
-- New Testament, St. Paul, 1 Timothy 6:10

...

Wrong: Consistency is the hobgoblin of little minds.

Actual: A foolish consistency is the hobgoblin of little minds,
adored by little statesmen and philosophers and divines.
-- Ralph Waldo Emerson from "Self Reliance"