One problem that often crops up when analyzing task and resource issues with Project 2007 is mishandling filters. After creating a complex filter that spans multiple columns, you may wish there'd be a quick way to turn off the filters for all the columns. Or worse, maybe someone sent you a project with filtering apply, and you can't easily tell which column filters to turn off.
Click F3. All the filtering is now removed. And, of course, this works in Project 2010, too.