We know what causes sickness. It's hard to imagine that for hundreds of years people had no idea where it came from. They assumed it was caused by spirits or some other crazy stuff. They never thought to look at RNA fragments with protein coats.
Snack foods. There didn't used to be snack foods. There was potatoes and maybe chicken.
Bathrooms are inside. I should probably spend at least an hour every day being thankful that I don't have to walk out into the cold to go to the bathroom.
SHOWERS. Imagine a world where nobody showers because they aren't invented. Everyone would be disgusting.
Not only do we have video games, but we also have wide access to books. People didn't used to have books. What did they do all the time? I don't know. Maybe sports!
News. Seriously, for most of history people lived without newspapers or any other form of news source.
Some amount of decision-making ability. You can pretty much grow up to be anything. You don't have to be a carpenter because that's what your dad does.
Birth control. People used to just have children. Lots of children. The average family used to have close to ten kids.
Cold medicine. I shudder to think.
Peaceful deaths. For most of history people died much younger than they do now, because pretty much any disease could be fatal. Not to mention safety regulations and living conditions nowadays. We now have at least the hope of dying peacefully.
Communication. There was no telephone. There were letters.
Police departments. I know the fuzz isn't particularly popular most of the time, but most of the people for most of the time lived in a world where soldiers were the regulators and the only court system they had was a monarch.
Comfortable clothes. Have you seen pictures of old British people?
The power to remove rodent and bug infestations from houses. I like to imagine that peasants used to spend hours chasing little roaches or mice around their cabins trying to chase them out. This might make a good cartoon.
Beds. What did people sleep on before beds? Ground and hay I guess.
Music. Guitars, pianos, even harmonicas were not easily acquired in the olden days.
Speaking of which, recorded music is another big one. You couldn't just listen to music.
Civilized government. I really like how we don't put political opposition to death. [Bush joke goes here]
Razors and scissors. Imagine trying to shave with what is pretty much a blunt knife.
Transportation. Traveling to another country was more or less a permanent thing back in the day.
Time. Clocks and watches were not very widespread items for a long time.
Check back later today when I update this post on the music of Final Fantasy,