What would be the case. have you ever connected to a server, thought it was a testing or development system, and only a split second after you pressed "F5" to run that command, realized that it was the production server? Yeah….me neither :).
To make sure that's never you, when you start SQL Server 2008 Management Studio (SSMS), stop for a moment on the connection dialog and press "Options". You'll see that you can select a color for the connection – I set mine to red for production servers, yellow for testing servers, and green for development servers.
Once inside SSMS, you can also set the default color for all connections – I do this and set them all to red, so that if I forget, at least I'll have that visual indicator to make sure the change I'm making is on the right server.
It helps on classifying the SQL Server Instances by Production, Development, Test or QA etc.