I love excel due to it's simplicity. But I had to learn more because of design projects of my company clients and manage administration stuff. I had either to hire a separate assistant or learn excel in more depth. So I choose the latter one, my friend Jasmine refer me to Chicago-excel-classes. I learned allot there, my teachers give me resources and time, which make learning process easy.
Tip for consumers: First note your requirements and before the start of classes inform your teacher.