'Twas brillig, and the slithy toves did gyre and gimble in the wabe

It's less an internal compass in the sense of knowing where North is, and more an internal compass in the sense of knowing that I need to walk in roughly that direction. I have managed to get confused once or twice though - for a long time at university, I regularly ended up with my mental map rotated 90 degrees after following a particularly complicated route through the maze of buildings (there was a quick left/right bit followed by another left that confused me). I still ended up where I wanted, but always found that route hard to reconcile with the actual physical layout.