I once thought it was as simple as "you gotta' believe". Believe in the Force and in yourself. Han is too cynical to buy into a bunch of "simple tricks and nonsense". Luke made a leap of faith when he turned off his targeting computer. His later disbelief is what keeps him from pulling the X-Wing out of the swamp. Yoda's trembling little hand is what sold me on his powers in that scene.

Jedi toss big stuff around far too easily these days.

Midichlorians, which I believe is actually the special additive that forever marks the person who whizzes in a swimming pool, undermine the OT. ;)