Outlook allows you to select multiple items with just your mouse.
The trick is to position your cursor in the very left part of the first column so that the cursor changes from pointing North-West to pointing N-E.
Here’s how it is normally:
Now position it a little more to the left and your cursor will change to be pointing up to the right (ie North-East):
Now simply hold down the left mouse button and drag and all the items you cover will be selected. No need to use the Shift or Ctrl key while selecting.
This works in other areas too. For example if you view your Contacts in Phone List view it will also allow multiple selections using this method.[See my Disclaimer if you’ve known about this tip for ages.]