How can I possibly pick just one thing? My mother, bless her heart, is an atrocious cook!
Let’s see, there was the eggplant (sliced and baked). I waited until she left the kitchen, and threw it away. Then she came back, saw my naked eggplant lying in the naked trash can, took it out, and made me eat it. 
Then there was the Spam (sliced, a dollop of bbq sauce on top, and baked). I just flat wouldn’t eat it. Fortunately I was old enough then to defy and win.
And I can’t forget the meatloaf! Small clumps of meat with more oatmeal than beef, watery tomato-ey juicy sauce with bran flakes floating around in it.
And the tofu eggs–she scrambled eggs and put chunks of tofu in it.
Speaking of eggs, she used to put chopped tomatoes and chopped onions in her scrambled eggs, along with some cottage cheese. One day I was at her house and at her request got the cottage cheese out of the refrigerator. It was moldy. She told me to spoon out the moldy portion and put the rest in the eggs. Needless to say, I didn’t eat breakfast with her that day.
What makes it hard is that on the rare occasions when I’m able to return to Utah for a visit, she always wants to make me one home-cooked meal. But my sister and I have found one that even my Mom can’t ruin, so we always praise it to the highest heavens and end up getting to eat chicken & rice instead of who knows what distasteful slop.
Oh yeah, one more. Mr. crazy4chaucer and I were married in November; his birthday is in February. His first birthday after we were married, my Mom invited us over for birthday cake. It was whole wheat orange-flavored angel food cake that was heavier than a brick. My sweet hubby tried to eat it, and I could tell that the effort was about to choke him. So I held his plate for him as he got up to do something, and politely held it low enough for the dog to lick it so he wouldn’t have to finish. He thanked me appropriately when we got back home. 