Can a mistake be just a mistake and not a lesson learned?

I asked a question yesterday about lessons learned from our mistakes and got some brilliant interpretations on this matter. As I read the answers and got to thinking is there ever something we do as pure as just a making a mistake? Or is there always a lesson to be learned?

Can you think of something you did or could do that is simply a mistake and no great lesson to be learned? Like grabbing baking powder when you were supposed to use baking soda?

Give me your answer and we can let the collective decide if there is perhaps a lesson to be learned! ;)