Correct. Air and gravity models in KSP are simple (though aerodynamics has been improved in the past years). Gravity simulation is essentially planet vs. active vessel, everything else is "on rails" and non-interacting. That means no Lagrange points, no sun-synchronous orbits, no need for station keeping.

However, mods come to the rescue. For flight, you have Ferram Aerospace Research, which gives you much more realistic (and much more punishing) aerodynamics, including all the interesting supersonic effects. For space, you have Principia, which introduces n-body physics, with all the Fun coming from it.