My last question was about the condition number of the stiffness matrix. This question is about discretization error (which is probably more important to most people). The mesh on the right side of the figure below (source) produced better discretization error than the "perfect" quality mesh on the left side even though the mesh on the right side has quads with angles close to 180 degrees.
I assume the creator of the figure (professor Christopher Roy) used a finite volume or finite difference method since he is a fluid dynamics specialist. Based on your personal experience using FEM, could FEM get a good discretization error using a mesh like the one on the right side of the figure?