F4 Function

The 'F4' is easily the most useful shortcut key in Excel. Basically it repeats your last command.
So say you changed the color of a font in a cell. Now click in a new cell and hit 'F4' and it will change the font in the new cell to the same color.Wonderful, right? Well what's great about this is that it works for nearly everything else in Excel too.Highlight a row, right-click and choose 'Delete'. Now highlight another row and hit 'F4'. It deletes that row.Whatever you did last, Excel will attempt to repeat the same command until you do something else. This works great for things that require you to go to the menus or right-click and make choices or click buttons that bring up more dialogs. It can be huge time saver once you get used to using it. As the help says, it doesn't work in every situation but most times 'F4' works great.