IE6 vs. the Acid2 test. It was only until IE8 that it passed Acid2.
Back in the days, Microsoft was single-handedly pushing the web forward, with around 1.000(!) people working on Internet Explorer and with a 100 million dollar budget to burn per year, with almost no-one left to compete. This was massive!
As I’ve been tinkering with the web for almost 25 years by now, I remember many of the stuff mentioned. IE/Trident gave us many great things, and sometimes was ahead of its time, lest we forget.