I read a little bit of Shewchuk's paper, which mentions the paper of Babuska and Aziz. This was quite interesting because (based on my understanding) while accuracy degrades when angles approach 180 degrees, smaller angles (granted the largest angle in the triangle doesn't become too large) aren't necessarily harmful to interpolation accuracy or discretization error (Figure 2 in the paper illustrates this well)

SourMongoose

Using the Delaunay condition, it seems a good indicator of a "good" triangle would be the area of the triangle divided by the area of the circumcircle, as this ratio becomes disproportionately small for skinnier triangles.

I read a little bit of Shewchuk's paper, which mentions the paper of Babuska and Aziz. This was quite interesting because (based on my understanding) while accuracy degrades when angles approach 180 degrees, smaller angles (granted the largest angle in the triangle doesn't become too large) aren't necessarily harmful to interpolation accuracy or discretization error (Figure 2 in the paper illustrates this well)

Using the Delaunay condition, it seems a good indicator of a "good" triangle would be the area of the triangle divided by the area of the circumcircle, as this ratio becomes disproportionately small for skinnier triangles.