IE6 was early 2000s, I remember it not being so great. CSS was starting to be supported but it was a minefield of un-supported features.
It was bad enough I swore off front end work and made a pact with myself to focus only on backend or embedded, for my own mental health :-)
IE6 was the most popular browser still during like 2006-2010. There was a point when Opera, Firefox, Chrome were already a thing, and they supported proper standard CSS and HTML, but 90%+ of users still used IE6 and you had to use tricks to support both standard and IE6 fuckery.
I do miss those times.