Missed chance to do something like:

  class User:
    def calculateCoworkers() = {
      this.coworkers.clear()
      for { d <- this.departments }
        this.coworkers ++ d.employees
    }

  user.calculateCoworkers()
  ... many lines after ...
  for { c <- user.coworkers }
    ... do something ...

Bonus points if you do half the calculation in the parent class and the other half in a child class. Double bonus points if one or both of them also hits a database.