Bitter much??

At my daughter's graduation last night, I ran into the parent of a former student. I had this student my very first year teaching, four years ago. I was teaching 6th grade math and science, and every teacher had to teach an elective. The teacher chose the topic of the elective, and I chose to teach the kids how to make sense of fractions using cookie recipes. We would spend a few days doubling or tripling a recipe, draw little cups and quarter cups of flour and sugar, etc. I called the class "Cookies 101." After we learned the math and figured out how much of each ingredient we needed, we actually made the cookies. It was a fun class, and none too difficult, I assure you.
So when I ran into this parent (who by the worked at the high school my daughter graduated from, so they knew each other) I said hi to her and then was talking to someone else. In the background I hear her say, "Cookies 101." I turned to her and said, "What? Are you talking about my old class?" She says, "That's the only class my daughter ever got a C in." She makes a C shape with her hand.
I wish I could have said what I was thinking... Lady. Get. A. Life. But I didn't. Instead I said, "How do you get a C in cookies 101?" Then I moseyed away. Really, I just think she needs to MOVE ON. I hope I never have to see her again.