One of the pieces of software I was most proud about was a data entry system for a P&C insurance company, the old policy subscription terminal-based system allowed for about 200 policies/hour by user, then they "upgraded" to a GUI that slowed them to about 20/hour and I built a desktop application that allowed them to go back to 200 policies/hour but with stuff like auto-filling, geolocation, error correction so the data quality was much higher.

I worked with the end users a lot to make sure the UI matched the workflow, iterated over several versions and it definitely paid off.