Modifying other people's software
Every once in a while, we all feel the need to modify something that someone else built. Sometimes those patches make sense to upstream, but not always. Sometimes they need a bit more time to bake, before they're ready to share with the world. Sometimes they're too specific to your environment. Sometimes it's just some personal preference, that the upstream wouldn't want to force upon everyone. And sometimes, just sometimes, you just want to run it yourself now, before it has had the time t