Hi Sean, welcome to the forums.
There are many reasons why people root their phones including but not limited to removing carrier bloatware, updating to a newer version of Android not provided by the carrier, flash custom roms and making complete backup images.
The danger is minimal, but with root access you can mess up your phone to the point of needing to restore it to stock just to get it to work again.
My question to you is what specifically do you want to do that requires root?