I like solving puzzles based on inherent complexity -- complications that arise in the data structures and algorithms of a piece of code. Any time spent fixing

I like solving puzzles based on inherent complexity -- complications that arise in the data structures and algorithms of a piece of code. Any time spent fixing complexity layered onto the minimal complexity by confusing or poorly-factored code sucks. For example: I enjoy solving a performance issue by introducing a time/space tradeoff. I do _not_ enjoy fixing a bug where a previous coder (maybe me) misspelled a variable name once in a 6000-line function -- that's just cleaning up a mess, not problem solving.