This may sound silly, but: The closest I've coming to building a "robot" was a simple little arduino kit. The kit was terrible, the parts defective, and you can imagine I was pretty sick of troubleshooting it after a time. These are things happening on my workbench with a small amount of automation code. I'd have been thrilled if it had just worked as designed.

Now, take three robots. One is wheeled, one flies by rotors, and another is rocket powered. Put them on a rocket, fly to another planet, and land them autonomously without wrecking anything. As a hobbyist I'd be beyond myself to just do ONE of those. On Earth. Let alone millions of miles away on a distant planet.

And to get video of it just days later, bounced across multiple orbiters? Mind blowing.