The pace of change, the reliable yearly cycles, they are hard to keep up with. However I just can’t deny that iOS dev is also consistently exciting. You know there’s cool new stuff coming all the time and a world of interesting possibilities that can affect a huge number of people in the world.
That’s the primary reason for me leaving web app development a couple of years back. Long before that, I had made Java mobile phone games and it was exciting for a short while. You had to do crazy things to fit an entire game into a 64KB zip file… but the novelty quickly wore off as cross-device porting pain and the extremely limited platform hit you.
I’ve been coding iOS since the first SDK was released and I am enthused by it now more than ever, which is pretty amazing. I’m motivated by making things people hold in their hands and use to make their lives better, and as developers we have so much power available to us.