My one particular stand out accomplishment was back in the Lumatic (RIP) days. We were a small app that provided pedestrian navigation in cities that included public transit. When we expanded beyond a single city we quickly learned we had to deal with timezones. The straightforward thing was to convert the times in each GTFS feed (the file containing scheduled transit times/stops/etc) to UTC. So I started digging into to the horrors of the tzdata format and spent a solid 8 hours looking into options there, hit a wall, tabled the project for a few days after which time an idea popped into my head: change the timezone for the process serving the city to match the timezone of the city. Sure enough, changing the TZ environment variable worked like a charm and unix did the rest.