Another one from Chris R....
One of the core ideas behind the new user interface is that people like to see what they're gong to get before they actually get it. This makes perfect sense to me - it's much easier to look at a picture and see it' what you want, rather than having to translate a list of options "Arial, Size 18, Underlined, Italic, Embossed, Red" into what that might actually look like.
This idea has given us Galleries, and Live Preview (to read about these as written by the man that led the team designing them - go here) which does make choosing between options so much easier.
But - what if you do something very regularly that isn't in the gallery?
Then you want to customise the gallery - which for most things is really easy to do.
Let's say that I write documents that use a particular style of heading a lot, so I want that heading style to appear on the ribbon in the styles gallery.
All I need to do, is format my text into the format that I want - something like this:
My Custom Heading
Select my text and choose "Save Selection as a new quick style" in the styles gallery.
And lo and behold, my style now appears in my gallery.
And if you want to delete it, simply right-click on the quick style you want to remove, and "Remove from the quick style gallery