You can sort or filter grids to display certain information/records. This can assist you in efficiently finding a particular record when there are a large number listed.
Filtering record can also assist you when you are wanting to do Mass Edits.
Filtering
To filter a column click on the filter icon next to the arrows and the name of the column.
This pop-up will appear were you can put in the value you want to filter by (be specific). Then click APPLY.
Different type of fields (date, picklists etc.) will have different types of operators.
As you can see the filter of 'Overdue' has been applied so only 'My Current Items' that are overdue are displayed.
NOTE: Remember to restore the grid to the original display you will need to go into the column filter and select CLEAR to clear this filter.