There has been much discussion

There has been much discussion in nerdy blogging circles recently about the need or otherwise of making your site look anyway half decent in old browsers. I’ve just taken a look at my viewer stats, and 10% of people visiting here are using cranky old Netscape Navigator 4.x. One person uses NN3 and another Explorer 2. This would suggest that a small chunk of my audience wouldn’t have much fun looking at this site if I made it very heavily CSS dependent.
The question is this: why do some people use such ancient browsers? Downloads are readily available for newer versions of these browsers, and surely they would make the whole internetwebthang experience Do you use an old browser? Why?