[deredede]

As the saying goes, there are two hard problems in computer science: cache invalidation, naming things, and off-by-one errors.

[ohthatsnotright]

You forgot Dates, Times and Timezones

[wildzzz]

Timezones: if you operate my code across timezones, you're wrong. Date and time: %Y%m%d_%H%M%S. Don't you dare ask for it to be shown any other way.

[Robin_Message]

Three ha you missed out rd problems;concurrency.