Elegant

By definition - pleasingly ingenious and simple. If good code was a tool it would not be a Swiss Army Knife, rather a tin opener.

Efficient

It is not wasteful. It is optimised to make effective use of resources available. Firstly for performance and secondly as to not tempt a poor refactoring.

Maintainable

Readable and obvious, documented and with tests. Another developer must be able to pick up the code and immediately understand its purpose.

Exposed

It must be difficult for bugs to hide, paths through should be clear.

Errors handled

Expected errors should be captured and dealt with. There should be no loose ends or black holes.

Focused

There is no slack code, just enough to get the job done. Its' intent is clear. Complexity is abstracted. There is little or no duplication.

Cared for

The author cared and it shows. Every possibility has been taken into account.