These findings display that heteroatoms, especially in delocalized pi-systems, are likely to lead to inconsistent optimized geometries. In particular, nitrogen, phosphorus, and sulfur atoms were found in all of the most over-represented descriptors and descriptor pairs. This is in line with our expectations, as QM treatments of sulfur and phosphorus are computationally expensive. Early force field development may have prioritized parameters for only the most common functional groups that involve sulfur and phosphorus. Our procedure has identified molecular fragments that yielded inconsistent geometries, and therefore can be improved upon in future force fields. Furthermore, nitrogen planarity errors are a known issue across force fields . We therefore believe that the descriptors identified by this procedure may be informative for the creation/training of higher accuracy small molecule force fields. Molecules containing these fragments should be included in future force field training sets in order to create more accurate and general small molecule force fields. We characterized molecules where SMIRNOFF was individually different