The design and construction of laptops violates a basic ergonomic requirement for computer usage, namely that the keyboard and screen can be positioned independently for appropriate viewing and typing. The reasoning is simple. With a fixed design, if the keyboard is in an optimal position for the user, the screen isn't, and if the screen is optimal the keyboard isn't going to be placed properly. If you work on a laptop regularly it is important that you have a separate monitor located with the top of the screen at eye level. It is optimal to use an external mouse and keyboard to allow more adjustability.