Alarm clocks
For twenty cents or so, alarm clock manufacturers can add a chip that not only knows the time (via a radio signal) but knows what day it is too. Which means that they can add a switch that says "weekends." Which means that the 98% of the population that doesn’t want to wake up on the same time on weekends as they do on weekdays will be happier (and better rested.)
This isn’t as complicated or expensive as my idea four years ago.
So why doesn’t every alarm clock have this feature? Because most people in that business are busy doing their jobs (distribution, promotion, pricing, etc.), not busy making products that people actually want to buy–and talk about.
There are very few products and services that wouldn’t get a lot better if people just tried to make them better.