And to avoid having any code ever fail. It was a formative experience to me to type in the source of a terminal emulator in C for CP/M that I ported to Microware’s OS-9 out of a 1984 Byte magazine that tried to do things the Either way without language support and noted about 4/5 of the code was error handling interspersed with the happy path. Either is not much better than errno in the end.