It shocks you.
Although you know exactly what's going to happen, you're not ready for the effect it has on your mind/body on the most basic level.
The sun's vanished!
Then there's the beauty of the spectacle, the ring of fire in the sky, the sudden drop in temperature, the eerie ashen glow not like twighligh or dawning either . . and the sudden cold gust of wind travelling toward the sun, making your hair blow at the back of your neck.

I saw the 1999 eclipse in France, by a lake, and I saw the shadow of the moon speed towards me across the lake. The only time you can stand in the moon's shadow is during an eclipse. And there'll be a bit of shadow on the UK Wednesday, and I think that's cool and groovy.

I don't know anyone that's seen an eclipse that hasn't been moved by it.