From your post it sounds like you are new to the S4. When I first got my S4, I was very disappointed with its overall performance. I had issues with WiFi, browser speed, touch accuracy and lag. I was ready to go to the store and get it exchanged, but knew that they would do a factory reset before exchanging the device. So I did a FDR (from recovery) before taking it in. The difference after the FDR was amazing. All of the issues went away. I got the phone from the Verizon Store brand new and I would have thought that the brand new phone (out of the box) shouldn't have issues, but evidently this isn't the case. I realize that a FDR is a PITA, but give it a shot and see if the phone isn't much better.