I think some people just "get it" a lot quicker than others. I don't know and won't guess as to why, but I have seen some guys solo after their first couple of flights, and others take a couple of years before they can take off and land one in one piece without help. I happened to be lucky enough to be one of those who got it quick, and I have no logical explanation for it. My instructor took the plane up the first time, trimmed it out, and handed me the box. He didn't touch the controls again until the engine ran out of fuel and he landed the plane. We refueled, started up, and he handed me the tranny and said "See if you can take off," so I did. When it ran out of fuel again I started to hand him the controls and he walked away saying "You don't need me, bring it in." That was the extent of my instruction.

This was about 15 years ago, no simulator, and no experience with R/C planes. I'm not exactly gifted in the area of reflexes or hand-eye coordination either, apparently just a quick learner or something.