Being on lab, working with some of the best engineers and scientists in the world. I got to talk to some amazingly smart and interesting people and learn about the work, as well as work alongside them. I was working on a project so profound - a spaceship that will search for habitability conditions on Jupiter's moon - that I really felt that I was part of something bigger and humanity's push forward.
What I wish was different
Government work can be a little slow and sometimes I felt like I wasn't being pushed to my 100%. I would have liked more challenging work, stricter deadlines and a tighter feedback loop so I could really do my best work and feel engaged at work.
Advice
Do not overlook the science talks. The best thing about working at NASA is the fact that you can learn about the amazing science that the organization does, so it's really important to get your head out of the bubble of your own work especially if you're not in a science group. Open up to new things to learn that may be remotely different from what you're working on.