The problem is navigating, I can do it easily in the classroom, set my plan etc etc its identifying land marks and not panicking if my plan don't work
I got lost in the circuit on my second solo when ATC gave me an orbit on the downwind leg.
Half way round the orbit I was getting dizzy and thought I had probably done a full circle already so I levelled the aircraft and flew off over the horizon....
Fortunately VDF and radar got me home again.