If there are some things you can count on with Sinful Colors, it's great cremes and multiple collections per season chock full of repromotes from their core collection. I get why they might insist on repromoting at least once in every collection; it'd be a great way to showcase their favorites, re-release some limited edition shades, and get some inventory moving on colors that would otherwise be lost in the large core displays.
Why Not is one of these kinds of polishes. I've considered it before but I always passed it over for other shades. It's a bright blue summer perfect creme. While this is a shade that's been duped since polish time immemorial, if you don't have a blue like this in your collection, it's worth the pick up.
Lavender, "lavander" (sic) on my particular bottle, is a muted lavender creme that drew my eye immediately. It's got absurdly perfect application. No streaking, no dragging, and perfectly opaque in two coats. I can't even approach this critically because there is nothing to critique about this wonderful polish.