In the 1980s, Eliyahu Goldratt introduced The Theory of Constraints. The core idea is simple but profound: Any system is only as fast as its slowest bottleneck.

Imagine a coffee shop:

• Step 1: Cashier takes the order (Capacity: 60/hour)

• Step 2: Barista makes the coffee (Capacity: 30/hour)

• Step 3: Server hands it to the customer (Capacity: 60/hour)

The throughput of this entire shop is NOT 60 coffees an hour. It is exactly 30. The barista is the bottleneck. If you hire a second cashier to take orders faster, you haven't helped the business at all; you've just created a massive traffic jam of angry customers waiting for the barista. To improve the business, you must improve the bottleneck.