I have a callus on my middle finger from eating yogurt. Reddit, what is the lamest reason for having a callus and/or abnormality on your body?

I have been eating yogurt like a madman the past couple of months, and in that time I have developed a callus on my middle finger (sorry for the poor lighting) from the way I hold the spoon when I stir the fruit on the bottom into the yogurt. Now it's up to you Reddit. What is your lamest reason for having a callus or abnormality on your body?