I've rarely felt like using opaques, (other then ivory or sediment bases) and pretty much steered clear of primary colours altogether.
Lately though I've been lured by the beauty of Special Orange, which has led to further dabbling with opaque red, yellow, green. I think it's a gateway colour:)
These disc flowers I've made a few times recently, great for earrings threaded on to hoops. I made Purple, Twilight Jungle and a few others, but the orange are definitely the happiest!