Imagine the blockchain as a huge digital city, and smart contracts are the automated machines that drive the city's operation — from DeFi trading marketplaces to NFT virtual galleries, each area relies on them to function properly.

Developing these digital machines is a meticulous task, but what is the common mistake many people make? Deploying contracts on the chain without thorough testing. It's like trying to land on the moon with a rocket but never doing a ground simulation test. It's not just that this thing "might" have problems, but that it "will" definitely have problems — it's only a matter of time.

For developers working on APRO or other advanced protocols, this lesson is especially heavy. A bug in a single line of code could be a black hole swallowing millions in funds. So before each deployment, you must ask yourself: Have I really tested this logic thoroughly? What about edge cases? Attack scenarios? Only after passing these "death tests" does a smart contract deserve to run in the production environment.