The argument sounds reasonable: fewer lines of code mean fewer bugs. Simpler to review, easier to reason about, less surface area for defects. Sounds great. It's true. But it's also incomplete.
The problem starts when backend developers treat production systems like homework assignments. In a single-process app:
you control execution. You know the order. Threads might race, but at least they share the same memory and clock.
Once you have APIs talking to databases, webhooks firing at midnight, async jobs on a queue, and three replicas behind a load balancer, the failure modes multiply: connections drop, messages arrive out of order, clocks disagree, and partial failures show up at 3 AM on Tuesdays.
Trimming code doesn't make any of that go away. It just hides the complexity until something breaks.
