Blindspot: 'hh' vs 'HH'

This is maddening! After working with .NET for more than 3 years, I just realized that I should be using HH (and not hh) to show 0-24 hours in a formatted DateTime. It is weird how I held this misconception for such a long time. If my workdays were from 00:00 to 12:00, then this could be justified, but that's definitely not the case...