I suppose 6 was good. . . for it's day.
Good lord no. No it wasn't. It was a pox on the internet. The pubic louse of web browsers. As someone who used to make a living doing back ends for dynamic, standards-compliant websites, here's how it works:
1 - Client has an idea for a super new website / internet wossaname
2 - Idea gets fleshed out in terms of technical specs, say a day or two of billable time
3 - Designer makes a nice standards compliant xhtml + css mockup, another week or two of billable
4 - Client is pleased.
5 - Developer builds back end and uses mockup to add a nice UI, add another couple of weeks of billable
6 - Client tries it, and is very pleased.
7 - Developer and Designer start to prepare invoices
8 - Client phones up at 11pm and says "what about ie 6? My mum/sister/significant other uses ie 6, and the test site looks horrible on her computer"
3 months or more of further billable time down the road, the test site looks almost presentable under ie6, but is now horribly bloated, and potentially broken on half the other browsers out there.
Supporting ie6 *tripled* the cost of website development, unless you *only* supported ie6. The only browser to manage to be worse was ie5.5/mac.
