Keyboard layouts possess and exhibit a rich history of stupid — though typical for people — decisions. Some of the initial decisions were reasonable at the time, but then somebody decided that it is a good idea to maintain them once they were outdated, and we are still passing them to the future.
At first, there were typewriters. If you ever wondered why the keys of a computer keyboard are not arranged in straight columns, and are not even arranged symmetrically – here lies the first answer: they are staggered to fit mechanical linkages of typewriters, so that those few old typists who once learned how to type on typewriters will never have to learn to hit the keys on a little different positions — as if Digital Revolution never happened! — even if they will use someone else’s modern computer. Well, actually they will have to, since even key sizes do vary among standard keyboards, but they still will have that familiar feeling of a screwed up arrangement – anytime, anywhere!
Furthermore, there is this ubiquitous QWERTY layout; some say that it was introduced to reduce clashing of typebars, others say that it is a myth, and in fact it simply was designed by a mentally impaired person. In any case, we still have it by default on computer keyboards.
A keyboard is still the most effective input method among available ones, so it may be desirable to fix those inconveniences. For mechanical layouts, Xah Lee provides a good collection of keyboard-related information, including reviews of particular models. For functional layouts, the two major alternatives supported by modern operating systems out of the box are dvorak and colemak; it takes a couple of weeks to achieve a comfortable typing speed after switching, if you practice. GNU Typist may help you to practice, and there are some websites for this purpose as well.
Fun fact: now staggered QWERTY layout is also the default for touchscreen keyboards, those where you can’t even type properly.
Sad fact: if you will look around, you may notice that the world is full of this.