What worked far better than you expected in marketing?

Most marketing discussions focus on failures, mistakes, and things that didn't work.

But sometimes the opposite happens. You try something with very low expectations and it ends up performing far better than you imagined.

It could be a campaign, a piece of creative, a landing page change, a messaging tweak, or something else entirely.

What worked far better than you expected in marketing?

And why do you think it performed so much better than expected?