Perhaps that's not a fair comparison. I'm starting to feel like you can see a green flash if you want to, as long as the conditions are right, and you're willing to watch. Here's one from 20 October 2014 (below). Eric and I were near the ocean at sunset and thought there was potential for a flash so we lingered until the sun went down. [You can click on the images for slightly larger versions.]
A minute later (at 6:27 p.m.):
Most of the time I see Snowy Plovers walking, running, or resting on the sand. On Saturday I was on the tidal flats in Bodega Harbor during a flood tide. The wind was calm, so the conditions were excellent for hearing shorebird calls. Snowy Plovers have a very quiet, subtle call, but I heard this small flock coming from a distance, and I knew I had a rare opportunity to photograph them in flight. I can do better, but it's a start!
P.S. I first wrote about green flashes last December — you can read that post here.