By not testing it properly before running it over the whole file system resulting in a few hours of extra work cleaning up the mess I made.

Very true. I used to do magic with xargs when working as a sysadm. Also a good way to mess up on a grand scale. Ask me how I know.

Waze is google these days. They bought it some time ago.

Take StreetComplete with you when you’re out and do pokemon-style quests while at the same time improve the map of the area you’re in.
It’s very fun and quite addictive, and the data you’re providing is open source so it’s not free labour for some huge company.

OpenStreetmap as an alternative to the closed source maps.

OrganicMaps or OsmAnd to navigate and StreetComplete or EveryDoor to improve it.