One of the many things my non-programmer friends needs to learn!

A matter of vision. Even in real world you don't look at a tree from above, that's why the root (at least I think so).

The more you go above, the more splits there are. It's flipped when rendering (e.g. image) probably because people got used to scrolling down for everything. :D

And a parent may kill its child after its function is done.

Does anyone know or care to guess how this peculiar naming convention came about? I'm curious

When working on data structures it's helpful to imagine the structure in Australia. Meaning a tree grows from the ground down.

(Or just flip the Y axis, but my method is more fun)