Remember cell phones before the iPhone came out? Big buttons, terrible internet experience, T9 texting? Then the iPhone was announced and released and now all phones have touch screens, a real web browser, apps that actually do really cool stuff and cameras that don't suck. The iPhone changed everything. Well the Macintosh computer was like the iPhone for computers. It changed everything. Before the Mac using a computer was just shy of learning a new language. It involved a lot of typing and learning various "commands" to make things happen. The Mac made everything much more intuitive and simple by making things visual.
You might think that Windows came before the Mac, but that's because you're young. Windows wasn't really usable until at least 6 years after the Mac was released in 1984, and many would argue (including me) that Windows wasn't really usable until 1995, and only just barely so. Thankfully I haven't used Windows since 1999.
The Mac was introduced on January 24, 1984. It was promoted before that with this ad, widely considered the best or most influential commercial ever run.
Then Steve Jobs introduced the actual computer to the world here.
While it may seem quaint that people were excited about such simple technology back then, it was a big deal. Desktop publishing was born this day. Using different fonts on a computer was made available to everyone. Being productive with a computer was now possible for people who didn't understand how computers worked. You could finally just use a computer to get lots of tasks done very fast without having to learn anything about how computers work. Sort of like how many of us use our cars.
If you're interested in the brief history of Apple, this video does a pretty good job of covering everything in under 10 minutes.