^Yeah, the perfect combination of affection/lust that isn't overdone. There's actually only one fanfic couple I've come across that's the perfect demonstration of that
Stories that have a balance between lust and love.
Great chemistry, especially when it's told through the dialogue. The characters don't have to be particularly snipy or witty in any sense, but if the situation presents itself and there's a great setting/scene, the dialogue will flow naturally and it'll show that the characters are good for each other.