Intermittent flicker, stutter and stalling sometimes when moving between spaces and switching between fullscreen applications and back to desktop. Desktop icon for external storage sometimes not showing up when plugging the drive/memory stick in, sometimes not even showing up in Finder despite being mounted and available in /Volumes. One and the same System setting that require admin privileges will randomly pre-fill my normal non-admin user's name instead of my admin's name. Moving the mouse across the notch in the top screen sometimes make the pointer live behind the notch, sometimes teleporting it across to the other side, randomly. Software Updates regularly telling me there are updates, despite non being available. Screen brightness sometimes starting 2-3 steps above/under last setting, unrelated to "dim screen on battery" setting. And lots more.