Rolling Hills: Make Sushi, Make Friends

One way to get all the 10 hats to unlock this achievement is to progress in the main story where you build a Wi-Fi antenna atop the Rolling Hills shrine and you'll get Min as a friend. She'll then offer a shop where there's items ranging from hats to recipes that you get spending points you earn completing challenges daily (the list refreshes every time you open the restaurant for service). At the beginning you'll have nine hats available, with all but the Crown (selling for 500 points) selling for 25 points. You'll also get awarded hats for finishing quests and hitting key relationship levels with friends (which can be expanded from events you can spend gold on at the Brew & Browse cafe and the friend you choose to spend that time with).