Is there some magic key to undo the last repositioning of the cursor? Having used GUIs for nearly all of my life I just can’t get it out of head that LMB is NOT select in Blender.:-? I keep carefully positioning the cursor, Shift-S snapping it to the grid and then bam I go and left click on something. 
The other cursor-related question is are there keys for moving the cursor by one pixel at a time? The arrows work in G, R, S modes, but I haven’t found any such way to nudge the cursor location.
Thanks 8)