I've done a few night flights with instructors (i.e. without GPS) and I think we got lost on every one of them, so he couldn't really fail me
Do you mean you couldn't fix your position to within 1 meter
There is very little convection at night, so conditions generally tend to improve compared to day time conditions (pending fronts and wot not!). But one aspect is the wind. The boundary layer is much thinner and hence lower meaning that at typical GA levels of 2 to 3,000' one can be faced with the sort of wind one would normally expect much higher with very little wind just at around 1,000 - 1,500'.
The other problem is shallow fog which isn't easily detectable from aloft meaning that visibility can be suddenly and significantly reduce at very low levels like landing.