My favourite invention is the computer. Basically everything we do in the modern world uses a computer in some way or another. I use a computer every step of the day: a computerised alarm clock wakes me up in the morning; I use a computer to communicate with other people, to entertain myself in various ways. It’s no exaggeration to say computers have built the modern world.
They’ve also opened up lots of new areas of science. There’s simply far too much data. It’s also opened up new ways to study complex systems like the weather and biology. These are both complex systems, affected by so many different factors, it’s almost impossible for humans to calculate. In order to understand these things, we need a lot of computer power!