Public transportation.

UBI. Not only is it viable but it works in improving everyone's lives, not just the people receiving it.

Socialized healthcare. A living minimum wage. UBI.

A permanent base on the moon. We should have had that 40 years ago, minimum.

Post scarcity society

the end of scarcity. that's a totally bogus concept that capitalism uses to keep the rich in power. we produce far more than the whole of humanity would need to feed and cloth themselves, and we have more houses empty than there are families. we could end poverty right now, we just choose not to.

We could be solarpunk. Like, right now. With everything using clean energy and plants everywhere.

Arcologies.

Dense housing with good soundproofing, atop commercial space, in a walkable neighborhood.

Wouldn't need rent control if there was more houses.

Telemetry free consumer products would be nice

I'm confident that we could set up permanent human habitation on the Moon or on Mars with our current level of technology, and that's featured pretty prominently in sci-fi.

I don't know if it would actually provide a cost-effective return, but I do think that it'd be interesting to see happen in my lifetime.

Free food.

Roof-top gardens everywhere! Like the launch arcologies in SimCity 2000. They looked cool as fuck.

Abolishing the concept of money. Probably won't happen but it would be pretty cool.

Socialism

Hemp as a replacement for plastics and synthetic materials. Food packaging shouldn't have a longer shelf life than it's contents.

Sunchips was using PLA, which is a step in the right direction.

Fusion energy. Man, we are so close!

Terraforming.

The formerly-water deserts can be terraformed by just digging holes at specific angles so the shadow protects plants from drying up.

It's sci-fi not like a "future robot" thing but more of a "hey we know the math we can do this reliably well" type of thing.

Also those expensive EEG headbands that track your brain during sleep and give you stats can be modified to change TV channel at specific brainwave values.

Alarm clock that reads my brain activity and only wakes me up at the point in my REM cycle, where i'll feel refreshed waking up.

The viewscreen from Star Trek. It's actually real but nobody really wants to use it.

Phones, tablets, and laptops have had video chat for years. Apple brought it to actual TV a couple years ago. The idea is you use the Apple TV set-top box, and you get a squared-S-shaped clip that mounts an iPhone to the top of a TV so the rear camera array can point out into the room. You pair the two, and your whole TV turns into a viewscreen, just like on the starship Enterprise.

I've explained this to a few people and the reaction is usually "okay why TF would I wanna do that?" So imagine a Thanksgiving or Christmas, or other "big family holiday" thing where you have that one person who won't participate because it's their partner's family's turn to see the kids or whatever... so, the Apple TV is like $100. And somebody is gonna have an iPhone. And these days, everyone has a TV, at least in the west, and they're 55" or bigger. So you get the TV in the corner of the room and you set it up so you're broadcasting the whole living room and maybe part of the kitchen or dining room, and you connect it to another family/part of the family who is doing the same. And your TV is now a window into that other living room, and people can go up to the screen and interact, or wave from across the room. Now if it's like Thanksgiving and it's based around eating, you could even run the end of the table up to the TV (so the TV is basically sat at one end of the table with no one in between) on both sides so when you look down the table, you're looking into that other room.

A moonbase.

How about a machine that can fold your laundry after it's washed and dried?

Augmented reality overlaying historical photos and 3d models so you can literally see history as your walking.

Imagine being able to visit The White City that was built for the World's Fair in Chicago. Or seeing New York before sky scrapers dominated the landscape.

I would just like complete control of my various web things. be able to restrict banking activity by source (so like lock my savings to only move between my checking and no where else), be able to make temporary credit card numbers that I can not only limit the amount of a single charge but max total that can be charged and daily charge and monthly charge and also be able to limit it to one payer. So like I make it and use it to pay for something than can go back and click on the the vendor payed and say lock it to only that vendor. Have an investment account where I can setup a variety of investments by percentage and have it keep those percentages as markets move. oh and have a local location for all my things where you can get any help including for their website although thats not exactly technology.

Nuclear rocket engines. A bit less ambitious than most of the responses, but most things here seem to either refer to technologies we don't have yet but seem within a century or so of developing, which doesn't fit the question, or vague consequences that one wants that tech to have without it being clear how our current technology gets there. But nuclear rockets definitely fit the question, because we have built and ground tested them before, decades ago even, we just haven't bothered to actually use the things. And they should theoretically make developing things like space industry or manned space exploration beyond the moon more viable, by being more efficient than chemical rockets while giving better thrust than ion engines do. They don't work well for launching from the ground, but since our launch abilities have increased a fair bit in the past decade or so, actually getting the things to space in order to use them should be easier than ever.

I never stopped dreaming about flying cars, I just think it's not gonna happen because a crash would easily kill people just sitting in their homes.

I think a moon colony was possible at minimum the mid 90's. I only think bureaucracy got in the way along with a very stunted space shuttle.