Question: Is it hard controlling the rocket and why?

Columbus Operations answered on 17 Jun 2016:

Joao: Yes, rockets are not easy to control. They are not like airplanes, with big wings and with ailerons. Not only that, they have to go much much faster than airplanes do, in order to take satellites (or people) to space.

But even harder than taking a rocket up, is bringing it down in a controller manner. SpaceX has just recently started doing that (in order to re-use them). Check it out:

And to get a better idea how hard it is to control a rocket, just try to balance a pencil vertically on one finger. 😉