ham radio, get your license and the exams will teach you what you might not know. Yes, if things go to hell a license won't matter, but if you get your license you will use it and practice with the radio and gain confidence. You don't open the wrapper on emergency gear and try to figure it out when the emergency hits, you practice and get familiar with it, so when the emergency hits, you have confidence in the tools. Same goes for shooting, first aid, emergency food cooking(which a lot haven't done), starting a fire, vehicle repair, etc.