One of the things that's fairly central to my PhD is the extraction of RNA. For most biologists, not a particularly complex task. Having been primarily a computational biologist in recent years, I find it's actually quite a lot of fun pottering around in the lab, learning a new process. Even now a couple of months after learning the process, I find there is always a moment of looking at the falcon tube in a concerned manner because there is nothing there when you rather hoped there would be something.
And a few hours later, there of moment of quiet, smug satisfaction when out of the centrifuge come a nice set of pellets in the bottom of the eppendorf tubes.