Netscape 4 was the bane of my existence, moreso than IE6 ever was, as an important client standardized internally on that forever so our entire platform had to be completely compatible with it. At least with IE you could do things in a user friendly way (perhaps at 2x the development and maintenance cost). Netscape 4 simply didn’t have the capability to do things we wanted to do experience-wise (like getting pushed content, I think?) without doing some extremely crazy and brittle workarounds at best (making it feel more like 5x the cost).
Also, IE4 was such a magnificent leap forward in the web that effectively enabled support for modern apps, which bought IE a ton of goodwill from me that didn’t wear off for a decade or so.