One of my friend recently purchased an iPhone and started using it right away. After couple of days of using it, he felt problems with listening when he is talking with people.

He thought there was some issue with the phone and showed it to me. I could not figure it out and suggested him to go to Apple store nearby. He went to Apple store and told the guy there about his problem. The guy took the phone to check what was wrong with it.

After checking the phone, Apple guy gave a weird look to my friend and handed him back his phone. My friend asked him what was wrong with it.

The Apple guy goes, "Please remove the plastic cover from your phone."

My friend literally felt dumb at that moment and so did I. :p He removed the plastic cover and voila!!