Tutorials you cannot skip. Don't get me wrong, tutorials are very useful for people who are either new to video games, or a certain genre, but when I already know how it works, I'd love to get into the game without further ado.
My brother and I, who are twins, have swapped some inside information between us. My adoptive sister, who's younger, has asked some questions about it at some point, and I've told her the basics.