When editing the boundaries of an object, say a floor, when you select a line you want to move, Revit comes up with random dimensions that the boundary line is x distance from. Sometimes Revit dimensions to a parallel line within the object, but most of the time it dimensions to some other random line in the plan. The default should be to dim to a parallel line within the object, and secondarily to whatever random thing it thinks is helpful (which is almost never the case). Small thing to fix, but it would make a big difference.
