Secondary dimensions are a very useful (and perhaps underused) feature of Google Analytics, since they allow you to segment your audience and your content by most conceivable combinations.
Bounce rate by country by operating system?
Visits by landing page by referrer?
In the Events reports – assuming, of course, that you have included event tracking code where it’s needed – you can take advantage of secondary dimensions to see which specific pages event are occurring on. If, for example, the footer on every page of your website links to a PDF or an external resource, you can apply Page as a secondary dimension to your Events reports and thereby determine not only how many events are occurring, but also where on your site they are occurring.
If you note a particularly high or low occurrence of events on specific pages, you could consider content or design changes as part of your ongoing effort to optimize your website’s performance.