Boolean modes for Selection tool: Add / Remove instead of Invert with Shift only
If you drag Selection Tool while holding Shift over already selected objects it deselects them. This can be very frustrating in some cases, for example if you have to carefully select and delete multiple patches of overlapping shapes. Instad of just holding Shift and dragging a selection box multiple times and then deleting, you have to select, delete, select again, delete and so on.
It would be nice for Shift key to only add to selection without deselecting, and (for example) for Alt key - to only subtract.
Currently, when making complex direct selections, the Direct Selection Tool only allows addition or inversion of current selection, either by drawing a selection box or by clicking individual vertices (while holding Shift). This is kind of silly. It would be way more straightforward for the tool to allow either addtion, subtraction or inversion of selected vertices (you know, using Shift, Alt of Shift+Alt, respectively).