Not using a feature X yourself means you might still need to deal with code written by somebody who uses the feature.

In lesser languages this tends to translate to "you need to deal with code using bizarre pre-processor coding and/or external code generators". glib*-stuff is a neat example for the former (although a lot of it's code and most of the architecture is overall bizarre, not just the pre-processor parts), things like Qt and some libraries parsing stuff using generated parsers / lexers are typical examples of the latter.