tldr; when performance is important, don't just use defaults, optimize. And learn how libraries and your OS work deep down at low levels. Even Python's default

tldr; when performance is important, don't just use defaults, optimize. And learn how libraries and your OS work deep down at low levels. Even Python's default IO performance can be improved in many cases, by changing buffer sizes or even bypassing the file io susbsytem and using memory mapped files. But no solution is right for all use cases. Like they tell you in school, premature optimization is the root of all evil. So don't worry about this until you need it.