Listening to music whenever at my Mac, I’ve come to realise iTunes shuffle doesn’t actually shuffle as you might expect.
That is, it’s not completely random. Tracks are selected based on skip count and play count.
If you’ve skipped a track a few times, it’s less likely to be played in shuffle mode than those with a higher play count.
Now, in need of some kind of method to make sure ALL of my tracks get played (I had some un-played from over a year ago because of iTunes’ lack of shuffling) I set up my own custom smart playlist to sit alongside the ‘Recently Played’ playlist.