OK... understood. It just feels that there is no push-back from bumping into something. In real life, when you bump into something the elastic deformations cause an opposite force to propel you backwards. Bump hard enough, and those elastic forces become permanent. Then there is also the mass of the two bouncy objects to consider.
Haven't looked at what's there now, but when last I touched it, the collision code computed the 100% elastic and 100% inelastic collisions via the momentum conservation method, applied a blend factor in terms of how elastic/inelastic the collision was, computed the resulting new vectors, and then applied the difference in kinetic energy as the damage.