I've seen a number of flavors of code reviews in practice:

  * Superficial - Omission of optional lagging comma
  * Valid in context - Quadratic logic on small finite set
  * Ensure intention - Task not completed/completed with adverse effects

Each takes progressively more effort, skill and context knowledge. There's a constant battle between resiliency and efficiency. There also tends to be a gradient of skill involved. Context is king when it comes to an opinion on this.