Linq: If you are using Linq-To-SQL, you call SubmitChanges() on the data context and it throws an exception (e.g. duplicate key or other constraint violation), the offending object values remain in your memory while you are debugging, and will be resubmitted every time you subsequently call SubmitChanges().
Now here's the real kicker: the bad values will remain in memory even if you push the "stop" button in your IDE and restart! I don't understand why anyone thought this was a good idea - but that little ASP.NET icon that pops up in your system tray stays running, and it appears to save your object cache. If you want to flush your memory space, you have to right-click that icon and forcibly shut it down! GOTCHA!
