The defendant wants to hide the truth because he's generally guilty. The defense attorney's job is to make sure the jury does not arrive at that truth.
“My parents were kind of over protective people. Me and my sister had to play in the backyard all the time. They bought us bikes for Christmas but wouldn't let us ride in the street, we had to ride in the backyard. Another Christmas, my dad got me a basketball hoop and put it in the middle of the law”