I would say food / nutrition. It's crazy how simple (not easy) it is to eat right, and how far, as a society, we are from eating right.
When you realize that a LOT of problems originate with food, it's becoming mind blowing. Probably more than half of deaths and health expenditures could be fixed with 'eating right'.
I tried to "AWS for meal prep" once. Basically, I predicted people would be doing more meal prep startups like Blue Apron.
The problem was that you had to own the supply chain to do it. Sort of like how websites used to have to set up their own servers, load balancers, and so on.
If you were doing meal prep, you'd have to look for boxes/packaging, negotiate (cold) transportation or look for riders, source cheap/clean food, kosher/halal, food storage, economy of scale, etc.
I wanted to set something up where someone could just tell a service to deliver a box with 50g of spaghetti, 2 cans of tomatoes, fresh basil, etc.
But it was too ambitious. Investors said to simplify it. Or that there was no market. Eventually me and my partner chickened out and just did foodstuff that we could deliver by mail.
It is not easy because food industry has power over what you eat, and they are making lots of money killing the rest of society!!!
You could compare that to the big tech companies if you are privacy concerned, they have lots of power over you and you need to be careful all the time.
I very much value healthy eating, but I'm not so sure how effective I am at doing so, and I've never been a "foodie". Some people deeply care about food -- about the taste, about the culture behind it, about the social experience of eating it. They get excited about going to new restaurants, and will talk about the food while they're ordering and eating it. (I tend to find these conversations a bit mystifying, and not have anything to contribute.) And, they tend to enjoy cooking.
Personally, this is not something that has captured my imagination; I regard cooking as a chore. If I have a lot of energy after work, then I'd rather go out than stay in cooking.
Perhaps, one day, I will "see the light" and become a devoted foodie. Until then, I imagine there is room for a startup to sell to me.
Coming from someone who felt the same about cooking for most of my life, I can say it happened almost overnight for me. Michael Pollan does a good job of dissecting the history of cooking/food and it's relationship to our health. Reading some of his work might be a good catalyst if you feel like giving it another try.
I've read some Pollan, In Defense of Food I believe. Certainly enough to convince me that nutrition matters.
I just don't get all that excited about food. For example, I'm currently visiting a research collaborator and friend away from home. Last night, even though he is unable to eat out due to health concerns, he insisted on taking me out to dinner. I was happy and grateful -- but despite the fact that he would be eating nothing, he was more excited by the menu than I was!
And more generally, I've been disappointed that eating together is the "default" social activity. Social life (at least at my age, and where I live) seems to be centered around getting a meal, drinks, or coffee. I've tried to expand things by inviting friends to more eclectic activities, but they usually haven't been interested.
The one exception is when I have a bunch of friends over for a party, then I do get excited about cooking. But that's an occasional thing.
It's much more than that. People often eat cheap and fast things because it's convenient. If healthier food can be cheaper and faster, it would be the default. It's sort of like electrical cars; there's a lot of potential but it's too ambitious.
I believe the problem is that institutional buyers are out-competing small families in the market. Large funds are paying cash for these houses to flip them and the people who actually need to homes can't make the same deal.
In the 1950s, the average new home was 1200sqft and held about 3.5 people. Today, the average new home is more than twice that size and holds one less person.
Since about the 1960s, we've also torn down about a million SROs. SROs used to be normal market rate housing. Now, most seem to be part of some transitional housing program for homeless people.
Personally I'd be interested in seeing more energy related things. Something that can displace oil. Something that can be more effective and reduce energy wastage. It has the potential to unlock a lot of cool things like desalination.
Optical routers would also be a cool thing if it doesn't exist yet.
Quantum computers has been in research for a while, but will do some interesting things when it happens.
When you realize that a LOT of problems originate with food, it's becoming mind blowing. Probably more than half of deaths and health expenditures could be fixed with 'eating right'.
I'm thinking more and more about this.