Yogi Berra
He DID say everything he said.

It is, of course, impossible for Lawrence P. "Yogi" Berra to say something he never said. And he must have said everything he did say. Both of these statements are, of course, a necessary consequence of logic.

On the other hand, whether Yogi said everything that people say he said, that's something else again.

What complicates the matter is that Yogi may have said some of things to which he is attributed, but that doesn't mean - nor did Yogi claim - he was the ultimate originator of the quotes. In fact, very few quotes are completely original - with the possible exception of "Awe is but the product of an uncomprehending mind", which as we know, has arisen from one of the deepest thinkers of the twentieth century.

That said, Yogi apparently did say quite a bit of what he was supposed to have said. For instance, regarding a certain restaurant both Yogi and his wife Carmen agreed that Yogi did indeed say "People don't go there anymore. It's too crowded." The only thing they couldn't agree on was exactly what restaurant it was.

But perhaps the best bit of Yogi's advice was a product of his sixty-five year marriage. Once a friend saw him standing in line to buy tickets at the Metropolitan Opera.

"Yogi," he said. "What are you doing here?"

Yogi replied in one word.

"Carmen."

References

Behind the Yogi-isms: Those Said and Unsaid, Victor Mather and Katie Rogers, The New York Times, September 23, 2015.

"Carmen and Yogi Berra: A love affair for the ages", Craig Wolff, New Jersey Star Ledger, March 8, 2014.