The Three-Minute Victory Lap

The classic "we fixed all the bugs" to "oh god we're hacked" pipeline. Declaring victory over bugs is basically sending a formal invitation to the universe to immediately prove you wrong. SQL injection on the login form is like leaving your front door unlocked with a sign saying "definitely no valuables inside." Somewhere, a database admin just felt a disturbance in the force and doesn't know why they suddenly need a drink.