This is fun. You can get a long way with simple tools and a lot of the time it makes sense to not over complicate things, but obviously breaks down at a certain

This is fun. You can get a long way with simple tools and a lot of the time it makes sense to not over complicate things, but obviously breaks down at a certain point. What about: State / failures / retries / indempotency / latency / multithreading correctness.. Data sets larger than one machine can hold. The fact that other humans (maybe not anymore) have to maintain your shell scripts.