When the Fdr is done without letting your previous apps be restored and with their settings in place, when your phone is done and finished with the reset, you'll then realize you have none of your apps on your phone. It's clean. Go to the market or the google playstore whichever you use and re-download your apps that you use. If you can't remember what all you had installed on your phone, if your or someone who doesn't back up their apps with a file manager app of some type then it's all good, just hop on over to the Google Playstore online and look at every app you have ever installed since you've had a smartphone.
It's like getting your phone at the verizon store the day you bought it out of the box. It's clean. Now just go put your apps back on. This was a fix when Froyo went to Gingerbread. It's a new system running now. A majority of the problems get fixed with a clean fdr...mainly because our app settings are backed up with Gingerbread settings and not ICS. It two different systems. It will geek a lot of phones out lol.
This is the fastest fix if you're having problems and not to lazy too implement the procedure. It works everytime. I hope I was clear enough for you? Any other questions feel free to ask. If I have a solution to it, I will try to explain it the best I can to help solve it.
This in return helps your battery life. Your system isn't fighting itself with app settings of two different software versions.