"Finding Nirvana is like Locating Silence" Jack Kerouac- Dharma Bums
The Golden Circle was something that is touted as a must see, if you only have a single day in Iceland this is where you should spend it. This is great marketing. It is easily accessible from Reykjavik and each of the stops have facilities to accommodate large tour buses which is something that is rare in Iceland. If you have one day you should drive towards Vatnajokull.
Gullfoss was the one stop on the Golden Circle that was totally worth the drive. It looked like you could get even closer than we did, but the trails were closed due to snow/ice. There are full facilities here, more akin to what you would see in the US.
We had never seen a Geyser in person, and were pretty excited about this stop. It was a bit... underwhelming. We spent the least amount of time here of any of the "major stops". Strokkur facts: It erupts every ~6min and is usually 15-20 meters high.
Þingvellir is the site of Europe's first Parliament. While there are a few great museums in Reykjavik (The Settlement Museum is really well done) this is one of the only true historic sites that we stopped at on our drive. Iceland has a fascinating history and this is well worth taking some time at.
It is also the site of the only visible continental rift. You can literally stand in two continents at once. It's like state lines....but better and the water is (unshockingly) a beautiful color.
After 9 days of navigating Icelandic roads and enduring the elements sometimes a guy just needs a little moss nap....