Outlook 2002 and later has a feature whereby it will remember the item you last had selected in a mail folder. So if you have item #5 of 10 in your Inbox selected, and you switch to the Sent Items folder and then go back to the Inbox, item #5 will still be selected. Without this feature, Outlook will always go to the top of the folder.

I find this to be a convenient way of keeping track of what I was working on, but I've heard from others who find this feature annoying. Fortunately for them, you can turn it off:

1. Run regedit
2. Go to HKEY_CURRENT_USER\Software\Microsoft\Office\10.0 or 11.0\Outlook\Options
3. Create a new DWORD valled PersistViewSelection
4. Set the value to 0 (do not persist)
5. Restart Outlook

And voila, no more remembering. The key can be deleted or set to 1 if you want to enable row persistence.