If you select the "fobtest" theme from the box on the left of this site as I write (although it may not be by the time you read this), your eyes will be assaulted. Red-on-pink, with a red spray-painted logo. It looks like a joke, and it is. But more than that, it isn't supposed to be here…
One of the classic problems with running a test instance, as I do for this site on my home box, is that it's easy to get confused and do things on the real instance that were intended for the test instance, and vice versa. The fobtest theme is primarily intended to ensure that I know when I'm working on FOB, and when I'm working on the FOB test instance. Even if I switch themes, the ugly red logo and favicon persists in the other themes, and out of context it's still pretty hard to miss.
I could tell you various horror stories about what has happened to me and to others when the test and live instances get mixed. Suffice it to say that I highly recommend figuring out a variant of this technique for your test instances too. It might save you some real grief—if you can avoid going blind first. (B)