I thought this story from David was worth re-posting here rather than being viewed only by a few developers on the developers forum:
Becoming a Moodle developer is like buying a big but old house with lots of rooms and moving into it with whole your family (which has millions of members). You must fix apparently broken things (like holes in the roof to stop water leaking in) and eventually renovate some parts of it. But at the end, you will just repaint the walls in the rooms you spend most of the time.
Somehow, your family members demand rooms that seem to work right now (e.g. they have a bed to sleep on, or a bathroom). Many of them are not interested in how the water in the bath gets warm.
There is certain border where you just must admit things were built this and this way ages ago and today we must live with it.