I’d credit my father who grew up in a rural area and then served in WWII. I grew up with horses and you really have to be prepared for emergencies with horses as there is often a wait for a vet in the case of an injury or colic. Once horse vets get to know and trust their clients they usually readily help the client prepare in the event of a delay of getting professional help. So being prepared with supplies and medications became a way of life for me. Then I did a lot of trail riding in the back country and thankfully was never separated from a horse, but that did get me thinking about what I actually had on my person as well as how to carry supplies so they didn’t present a further hazard in the event of a fall.
I don’t do that much back country riding anymore, but do lots of day hikes with my dogs as well as living on acreage and still having a couple of horses. My kits vary but even just out on my own place with my dogs, I always have some first aid supplies in a small pocket kit as well as a cell, bandanna, multi tool, knife, light and in the winter months usually a heat sheet. When I leave the pavement for hikes I always carry a pack with supplies as well as Doug’s kit souped up, a small FAK, and tools in my pockets.
With all that said, it still takes practice and training. So get first aid training, practice fire building in less than desirable conditions, learn reading a map and navigating with a compass. If you have animals get first aid training for them too, dog clubs and horse clubs often offer seminars for a very minimal cost. Camping is a great way to practice and figure out what works or doesn't work for you.
Living in earthquake country I’m in the process of making a small urban kit to keep in my purse sort of Doug’s kit minus some of the wilderness items like the fishing kit, signal mirror, and compass. This site has some great ideas and expertise.