Memorable but unremembered

On I65 one of the side roads leads to Walesboro. That name always reminds me of the line in "A man for all seasons": "Why Richard, it profits a man nothing to give his soul for the whole world... but for Wales?" Except, of course, that I generally only remember the last 3 words, and have to reconstruct the rest. It's a memorable line, but I can't remember it. I'm even worse at getting all the bits in order for the unforgettable passage that ends "Yes, I'd give the Devil benefit of law, for my own safety's sake!"

I've an excuse when an earworm of Hava Nagila turns into mud (or into Halva Nagila, or into Harvey and Sheila, or just repeats like a scratched record), since I never learned the actual words and my ear isn't tuned to pick out the phonemes of Hebrew.

But English is my native language. When my mind says "This is important; stuff it in one of the quick-access slots," how come half of it falls on the floor? I summon up a teaser or key line or executive summary, but most of the details are missing.