The major theme is that we are not allowed to do anything constructive/productive. Just as God stopped creating the world on the seventh day, we stop our part of making the world.

This is broken out into fine detail in the sources. There are 39 categories of work listed, covering agriculture, food production and cooking, textile production, building, and a few more.

When electricity came along there was a big debate among rabbis if its use comes under one of the existing categories or not. Nowadays among Orthodox Jews it's universally agreed that it does. This obviously wipes out a lot of modern life - not just the internet but even switching on lights, etc.

Reading, learning, eating lots of good food with the family, meeting friends, taking your kids to the park - all totally permitted.

As kids, yes it was sometimes annoying. But now it's amazing.