The senior who writes the most boring code
The clearest sign of a great senior engineer isn't clever code. It's how unremarkable their code looks — and how rarely anyone has to touch it.
Junior engineers write code that's impressive. Senior engineers write code that's invisible. The most experienced people on a team often produce diffs that look almost too simple — because they've removed the parts that would have looked clever.
Why boring wins
Boring code is easy to read at 2am during an incident. It survives the next refactor. It onboards new engineers without a tour. It does what you'd expect, in the order you'd expect, with the names you'd expect. Boring code is a kindness to future you.
Promoting for boring
If your promotion criteria reward visible complexity, you'll get visible complexity. If they reward systems that quietly never broke, you'll get more of those. Calibrate accordingly.
The best code looks like anyone could have written it. That's the point.