What's So Weird About Einstein's Observations?

The behavior of light can really only be understood if we accept this dual reality that light is at once both a wave and a particle. I don't think really anybody believed it at the time though. It would be years before it became widely accepted. And surely, around 15 years after Einstein wrote his paper, he won the 1921 Nobel Prize in physics. But that was only after years of experimental evidence that kept showing that this weird wave particle duality of light really is true.