I once met a professor at a quantum chemistry conference who argued with me that I could not converge on the exact eigenvalues of a helium atom (assuming a simplified Hamiltonian with a few Coulombic terms). He stated the oft repeated mantra that "the Schrödinger equation can't be solved for any element other than hydrogen", so I wrote a program that brute force diagonalized the Hamiltonian to demonstrate otherwise. He was confusing the notion of a closed-form solution (an analytical expression that gives the solution in terms of specified elementary functions) with that of a numerically exact solution (one that converges on the exact solution but can't be expressed in terms of specified elementary functions).

Another professor who was teaching a course on statistical mechanics once said that the single particle wave function is more fundamental than the multi-particle wave function. Nevermind the fact that his research involved density functional theory, which famously fails on those cases where the molecular wave function can't be well approximated using a product of single particle wave functions.