Walter Jon Williams said this quote

“ TV stars are cool. Even if their characters are less than admirable, they come across as somehow sympathetic, maybe even neighborly. They are, after all, people you invite into your home every week. If you don't like them, you won't watch them.Movie stars, by contrast, are hot. They have to blaze so fiercely that they fill a screen forty feet high and demand the attention of a crowded theater.That's why very few TV stars have graduated successfully to features. It requires not only different skills but a different personality. You have to go from amiable to commanding.Likewise, some movie stars are simply too big for television. Jack Nicholson is riveting on-screen, but you wouldn't want him in your living room week after week. The television simply couldn't contain his personality. ”