TL;DR

Answer 1

• Deploy experimental feature on Friday, it crashes the whole system
  • Never put yourself in a position to make mistake
    • TDD
  • Not a good idea to deploy big stuff on Friday
  • Think about the risk before deploy
  • Confirm after deploy asap
  • Don’t be afraid to move fast and break things
    • Mistake make you grow

Short summary

We did everything he mentioned besides TDD, just keep it as a reminder.

Answer 2

• Early optimization is bad
  • Lower readability
• Readablility > Performance (in most cases)
  • only tune performance on bottleneck
  • compiler is smart enough to optimize
  • Note: firmware have performance > readability

Short summary

I argee the points. Premature optimization is bad, but sometime it is hard to determine what is premature optimization. We should have Readablility > Performance unless we are doing very low level stuff.

Answer 3

• Ask for code review, read code of great engineer

Answer 4

• Abuse OOP, don’t forget single responsibility
• over-complicated
• over-simplifying
• extreme failure test
  • shutdown and turn on the database
  • flush all the cache

Answer 5

• Reinvent the wheel
• Code before think
• Use the wrong tool, simply because it is popular

Answer 6

• Infatuated with the process of building the product
  • Get things done, engineer are solving problems
• Ingore code written by others

Answer 7

• Someone make his AWS key public…
  • Luckily, Amazon recover the cost

Summary

• Read others code to learn
• Study TDD
• Focus on problem solving
• Code before think
• Think about risk before deploy

Reference: What are the programming mistakes most inexperienced programmers make?.