I carry a powerbank and various USB C adapters so if someone’s device dies I can help them out. It is a lot cheaper and smaller than carrying around seven different cables.
On top of that I carry Tylenol and bandages.
I used to carry a full first aid bag but kept forgetting to restock on supplies.
Gotta be real glass or ceramic. Hate the metallic or plastic-y taste of most. Love the bodum ones, forgot what they’re called