Mug-cake mix at home
Not really.  If you mix up normal cake batter with the directions, and microwave it, it will cook.  It doesn't taste like a baked cake, but its certainly edible.
Actually, specifically, you add Angel Food cake to other cake mixes.  The reason is that angel food cake mix usually contains powdered egg whites.  The other option is indeed powdered egg, but angel food cake mix is more common in these recipes.
Mainly its about expectations.  Many things 'work' in the sense that they're edible, but they may not resemble the product you think they should.