What's an idea you have that should be an actual thing?

I think there should be pedestrian, bike routes separate from cars, like storefronts should face both ways, and the intersections with signals, but where practical should have bridges for the walkers, so they don't have to deal with the cars.

I also really want replicator tech, want to be able to use any input to get basically any output, at least in terms of materials. Throw in the trash, it is sorted into its component elements (safely) and then those can be combined to make clean water, salt water, building materials, whatever.

I want also a floor and walls that eat the dirt, and clothing fabric that can cool even in humidity.