Acting through hands is important. They should never be limp. They always have an energy to them. When drawing hands, especially for animation, you should always focus on drawing the expression or action and making it super clear, rather than the anatomy--the anatomy comes last. It is especially important that they be clear when working in TV animation where the animators are overseas--the animators probably won't be able to ask the story artists what the hands mean in a certain shot if the animators are in Korea and the story artists are in California, USA.
Hands should also never be limp or fanned out (like pancakes). Hands always have a purpose. This is especially evident in dance and performance work. Below is a great example of expressive hands: