Originally Posted by asiandoood

from a non geeky speculation/guess:


qui-gon knew the power of immortality to become one with the force, but not appear as a force ghost.

yoda was taught by qui gon this power, and yoda had more time to learn this power and possibly mastered it [to reappear as a ghost] as did obi wan.

annakin always wanted to know the power and probably studied it while he was under the influence of the dark side of the force.