Are there any jokes made because of mistakes?

One day, a farmer felt sick, so he went to the hospital for examination. The doctor said that blood test, urine test and stool test were needed, and then he was given three utensils. After a while, the farmer came out of the toilet and said to the doctor, doctor, I have swallowed blood and urine. I really can't swallow this shit! The doctor smiled at that time.