Every dependency is a liability.
Code you didn't write is code you can't vouch for. Every library, every framework, every third-party service is a promise someone else made. We keep the dependency tree short and we know what's in it.

If it works but nobody knows why, it doesn't work.
Coincidence is the enemy of reliability. A system that passes every test but can't be explained is a system waiting to fail in a way nobody can fix.

Constraints breed better engineering.
Tight memory, slow networks, limited power. These are the conditions that force clean design. Remove the constraints and you get bloat. Embrace them and you get craft.

The easiest code to maintain is the code that doesn't exist.
Every line of code is a future liability. Before writing something new, we ask whether the problem can be solved by removing something instead. The lightest systems carry the least.

Error messages are user interfaces too.
When something goes wrong, the error message is the only thing between the user and frustration. It should say what happened, why, and what to do next. Anything less is a door closed in someone's face.

Security is a design constraint.
It belongs at the foundation, next to memory layout and power budget. Bolting it on afterward is expensive, fragile, and usually too late.

Ask why before asking how.
The most expensive mistake in engineering is building the wrong thing well. Understanding the problem comes before choosing the solution.

Efficiency is a form of respect.
Respect for the user's time, their hardware, their battery, their bandwidth. Software that wastes resources wastes something that belongs to someone else.

Good defaults save more time than good documentation.
If the system does the right thing out of the box, most people will never need to read the manual. Sensible defaults are invisible kindness.

A clean interface hides a thousand decisions.
The simplicity a user sees is the result of every decision made underneath. Easy to use means hard to build. That's the job.