Did you lose your outline levels in subtotal mode? Use Ctrl+8 to bring them back (or hide them) while keeping your actual subtotals visible.
Hide a row quickly (Hint: add Shift to Unhide) with Ctrl+9. It works on multiple rows, too. Rows are easily unhidden, so don’t use this to “secure” data.
Create a table from anywhere inside a well-built list with Ctrl+T. You don’t have to select all cells, as long as the table has no completely blank rows or columns.