Effects are virtually identical to styles and you use them to change the appearance of your document in exactly the same way. The difference is that effects do not have names and so are applied once only. They are useful for quick one-off changes but less so if you want to be able to make consistent changes to a large worksheet or document.
If you make changes to the ruler or toolbar settings while any cells are selected, the changes will be applied to them as an effect.
If no cells are selected:
See also: Applying effects