Alignment used to be a big problem with CSS. Before improvements like flexbox and grid, people used to struggle to do basic alignment, like horizontal or vertical centering, or simply spacing items apart. There were a lot of (ab)uses of floats, tables, and relative/absolute positioning used for layout
IE, Chrome, Firefox, and Opera had their own separate rendering engines. IE was also notorious for running with "quirks mode" out of the box which basically meant that IE was render pages in a non-standard way by default
It was possible to develop things correctly, of course. But resources, both in terms of availability of documentation as well as time, were not as easy to find as they are today
It was tedious, sure. CSS2, especially, was just powerful enough but unstandardized enough that nothing worked quite right universally. Now, I can jump into CSS3 and throw a flexbox down or a grid and just tell it exactly what I want, in 1/8 the code and it'll work across all major browsers.
IE, Chrome, Firefox, and Opera had their own separate rendering engines. IE was also notorious for running with "quirks mode" out of the box which basically meant that IE was render pages in a non-standard way by default
It was possible to develop things correctly, of course. But resources, both in terms of availability of documentation as well as time, were not as easy to find as they are today