IP and How to fake Ip

Why you must fake Ip?
First you want to know your Ip go to : www.google.com and type keyword :"showip"
then you'll find more site that show your real IP.
Or type http://showip.net or http://ip2location.com
You will see your real Ip.
If you have one site and you want access this site but it say : Can't accsess or Site prevent you .
How can you access this site?
If you want to hide your location and prevent hacker attack you .How can you do it?
If you want to have more accout at one site .But this site say : You already have account.How can you creat more accout? ..ect
Then this is best to do it: Fake your IP.