Actually he seemed like a great, interesting guy and I understand Harry to get frustreated by Draco's apparition when he is just about to have a new boyfriend.
It just when Rodrigo "muttered something that sounded like, “Wondered when you would get the nerve” and was probably even more insulting in Spanish", I wondered about the word "insulting".
I thought he perhaps was arrogant but hid it well up to that point.
Maybe it was not the way to interpret it.