The best system I ever worked with looked incredibly simple. Small, clear functions. Lots of "set a few variables, run some if statements." Incredibly unassuming, humble code. But it handled 10s of millions of transactions per day elegantly and correctly. Every weird edge case or subtle concurrency bug or whatever else you could think of had been squeezed out of the system. Everything fit together like LEGO blocks, seamlessly coming together into a comprehensible, functional, performant system. I loved it. After years of accepting mediocre code as the cost of doing business, seeing this thing in a corporate environment inspired me to fall in love with software again and commit to always doing my best to write high quality code.

EDIT: I think what made that code so good is that there was absolutely nothing unnecessary in the whole system. Every variable, every function, every class was absolutely necessary to deliver the required functionality or to ensure some technical constraint was respected. Everything in that system belonged, and nothing didn't.