&quot;vast majority&quot;?  Maybe.<p>But anything which uses matrices (aka. systems of linear differential equations), always runs into some pathological cases.  Quite often, they aren&#x27;t even uncommon.<p>Systems which have vastly different time constants in the same system are <i>ALWAYS</i> a problem.  Simulating RF circuits or phase locked loops is always an issue.<p>Computational fluid dynamics always has boundary conditions that challenge infinity&#x2F;zero and drive the solver crazy.<p>Something as pedestrian as simulating <i>basic cotton cloth</i> accurately is problematic (the warp&#x2F;weft redistributes energy on a much faster time scale than gravity pulls the cloth down).<p>A lot of people did a lot of research and put in a lot of programming hours to make solving these problems relatively easy without understanding the gory details.