Macros

Lots of reasons - you can essentially record actions you complete on the sheet. Say i have loads of tabs with different data and a menu tab. For navigation I put loads of buttons on the menu tab. I can assign a macro to each button which will open the appropriate sheet when the button is clicked. To record the macro I just press record macro button, name it, complete the action (in this case select the tab I want to open) and click the stop button. Now when that macro runs it will open the sheet automatically. Just one basic example but possibilities are endless....