My sister and I just figured why the Guide Beret appears not to work. When you click on it in the Item menu to use it, it will bring up the purple subcursor. If you click again, and use it on yourself, the timer won't finish and nothing will happen. What you have to do is use the subcursor to target the person wearing the Sprout Beret, and use your Guide Beret on THEM. Then it will activate and lower your level.
Stupid SE, making things so clear to use. e_e



