I was doing one of my first solo cross countries in Florida, on a Flight Following from Orlando Approach. My first time ever on Flight Following on my own. As all N-reg aircraft registrations start with, well, an N, it is common to call yourself "Cadet 250FT" instead of "N250FT". But apparently not everybody does that. So it took the controller quite some attempts to get through to me, calling me "N250FT".
Wasn't the worst what happened during my stay there. There was this other solo x-country student who was self-announcing his way through the circuit at Sebastian, an uncontrolled field. Only when he actually landed and noticed a fairly tall control tower flashing green and red lights at him, did he realise he was not at Sebastian at all, but at Melbourne International. Oops.