Android actually is a bare minimum operating system or platform that is fit into a low end computing hardware. That are primarily, smart phones and your handheld tablet (known as "TAB", i-Tab, Galaxy Tab etc.). It is designed to that type of devices, as many people probably don't feel very much convenience of carrying a laptop-size mobile phone everywhere they go.
But why do we need to hack the Android?
The answer is simple. Each and every Android OS relies on a stripped down Linux kernel to operate with. It is but undeclared sibling of Linux. It shares Linux file structures and behaviors. Android inherits the capability of Linux and function. For example, Android has two types of users. First, the ordinary or the end user, that is you. Second, the administrator as Linux allows it to the level much beyond of Windows 7. A power user that can do anything that makes the system goes for the better or for worse. Which is also you, should the hacking succeeded.
Still, why do we need to hack the Android?
Because as I said earlier, Android is designed to operates on a low end hardware. Every storage, space and memory counts on nearly all phones or tabs that you bought. So if there is anything inside there that can be put away, theoretically it shall behaves better and runs faster thereafter, likely.
Basically, by hacking and gain the administrator access to your Android, you will be able to
i) Remove the manufacturer specific and often bloated bundle wares that come with the phone. Most of them don't even being used from the time you bought the phone till the day it broke down. So release the space and speed up the phone.
ii) Install every app that you wish with root access. For some apps, root access install means extra functionality.
iii) You get a total control of your system including the capability to damage your system, Yeahh, freedom to break of sort. That is the spirit of a hacker!
First thing first. A disclaimer, do it on your own risk. I shall not be held responsible for any damages that may caused to yourself, your mobile phone or tab etc..
Please be forewarned that you may void the device warranty as well.
But c'mon, you wanna hack it right? So, about the gaining administrator access in Android. They call it root, rooting the Android. Search Google about this or simply click this LINK.