The eigenvalues of the one-electron reduced density matrix -the natural orbital occupation numbers (NOONs) -are non-integer, deviating substantially from 0 and 1 (or 2 for restricted models). 6. The amplitudes of Coupled Cluster (CC) theory, especially T 1 and T 2 of CCSD, become large. As the connected portions of triples amplitudes and higher become significant, the corresponding residuals remain large such that no finite truncation is well-posed. 7. Two-body spin or particle correlation functions, e.g. ⟨S 0 • S i ⟩ or ⟨n 0 ni ⟩ in a real-space site basis that do not decay exponentially. This idea of long correlation lengths is familiar to statistical physics.