The rhythmic aspect is not the biggest problem either. I play drums primarily, and I find some similarities between permutations of stickings of drum rudiments, and rhythm on the piano. So I can make reasonably quick progress in that regard.It really is the technical aspect. I lack dexterity, speed, hand independence and strong 3-4-5 fingers. As I've never had much formal training, it does knock my confidence. Worst of all, I think the musicality of whatever I am playing suffers, because I have to focus an inordinate amount of attention on the behaviour of my fingers. It doesn't seem natural. Does that make sense?