Blender makes it a point to use as many buttons on your mouse as possible. You have five fingers; you may as well get full use of them. This table gives you some of the most commonly used mouse behaviors.

Action Result
Left-click Place 3D cursor
Ctrl+left-click (edit mode) Quick-extrude
Ctrl+left-click+drag Lasso selection
Right-click Select
Shift+right-click Add to selection
Alt+right-click (edit mode) Edge/Face loop select
Middle-click+drag Rotate view
Shift+middle-click+drag Pan view
Ctrl+middle-click+drag Zoom view