The only thing slightly wrong with your analogy, LEM, is that KVA is the vector sum of KVAR and KW, not the algebraic sum. KVAR is 90 degrees in advance or behind KW depending on whether the circuit is overall inductive or capacitive.
A final piece of trivia for you. Because the effect of capacitors is opposite to the 'back emf' effect of motors and coils an ideal circuit can, in theory, be adjusted by adding and taking away capacitors so that the KVAR reading is zero. This is called a resonant circuit.