- Every time you refresh you need to clear your filters before you refresh.
- Every time you refresh you need to re-do your sorting.
Change report filters!
Click the Edit button next to Reports and you can change the filters without going back into Salesforce! (Waiting confirmation if this is available in the free version).
Way more notes to be added here, but quick tips are to ensure your Settings are as you need them (200 DML operations at a time is default - and usually you will want to uncheck Ignore Blank Values so you can clear data from fields).