Very true. Gmail does that very well, but that's not something you cannot solve if you are very disciplined on how you use, store and archive emails. Gmail makes it frictionless, and that's probably one of its biggest assets, but in some workplaces, as you mentioned, people are forced to use Notes or Outlook and you learn to live with it. It's not always as frustrating as you might think. For example, I am certainly much more "messy" in the way i use email with Gmail since I know I can find things easily, but that may be a disservice to act this way in the end. You form bad habits.