[Totient]

Satire, aside, I think a very short addition to the last line holds a lot of truth:

"A hash is simple. A hash is fast. A hash is all you need to start with".

I can think of plenty of good reasons to stop using a map/hash/associative array in code, but I can't think of very many good reasons not to start coding with associative arrays as your default data structure. If there's a performance/memory problem, fix it later. I've seen a lot more code suffer from premature optimization than I've seen suffer from using data structures that were a little too inefficient.