If you're the final user of an API, then yeah, go for gold and change whatever you want. But if you're working in a team (or contributing a patch to a Github p

If you're the final user of an API, then yeah, go for gold and change whatever you want. But if you're working in a team (or contributing a patch to a Github project), and you override something crutial like String.subtring(), then things could get out of hand.