As a programmer I would definitely say ChatGPT. I mentioned it to my co-workers because I could see the potential immediately. As we dug in more we discovered GitHub Co-pilot. Wow! What a great product with so many use-cases. It certainly changed the world.
It was helping me in so many ways! As a technologist and musician, there were many things it did well for me!
It was obvious what a great tool chatGPT would be in my life. While it may not have all the answers and can sometimes be wrong, it is great for the things I listed above and has been a great help to me in my career and life.