Been working on the same project for close to a decade now: remote patient monitoring in the healthcare sector. (Mainly chronic) patients get to live longer and more normal lives knowing that any worsening of their condition is caught early on by clinicians and as a result the national (usually European) healthcare services save a ton of money by avoiding (re)admissions to their hospitals, one of those rare win-win scenarios. Improved the lives of thousands of patients over the years.