I automated my job at a company. I did not tell management for a week after but was then bored. It took another few months of me nagging them for more work before the believed me and gave me another project.

It was a business critical application I inherited that was highly unreliable, my job was to keep it running. I just reworked the code so that it ran reliably and was resistant to outages etc. I also added in a few scheduled tasks etc to keep it ticking over