I have no excuse.

"Sir, there is no excuse." you reply, "I try, but no matter how much effort I put forth there always seems to be something I cannot do. I think that maybe I am just not capable."

"I appreciate your candor," I replied, "but I am afraid I cannot agree with your conclusion. You are perfectly capable of keeping yourself in proper clothing; while you have a number of demerits for your dress, they are hardly an everyday occurrence as they would be if you were incapable. Your problem is that you do not consistently apply yourself."