Depends on what you mean by interaction. Sound is a difference in pressure, these pressures can add up. Light is electromagnec waves which can also add up. Its like two humans pushing an object, the object will feel double the force, but the humans are not necessarily interacting. Light can interact with each other under the presence of atoms if the light is strong enough. For instance two photons can combine into one with doubled frequency: e.g. green laser pointer.

I would say quantum physics is mostly math. Some people understand math better than others :)