Over-engineering is a common cause: simple solutions can be deceitfully difficult to find. That being said, additional indirection layers are usually justified by the overall architecture, and — assuming they're reasonable — can't always be appreciated locally.

  « I'm always delighted by the light touch and stillness of early programming languages. Not much text; a lot gets done. Old programs read like quiet conversations between a well-spoken research worker and a well-studied mechanical colleague, not as a debate with a compiler. Who'd have guessed sophistication bought such noise? » (Dick Gabriel)