My Grandma, Not Roberta

 My grandmother's name was Beatrice, but her nickname was Bobby. At some point in their long marriage, my grandpa started calling her "Roberta." 

Grandpa inexplicably wearing a bike helmet and "Roberta."

I can follow the Bobby -> Roberta logic path. 

It's kind of funny in the way that my grandfather was kind of funny. He'd call grammy Roberta like your mother calls you by your given name when she's had just about enough of you. Or when she needs you to come and do something for her. 

Meaning, he called her Roberta a lot.

After my grandfather died, the Mackoveks who lived next door for 50 years or something came over to offer their condolences. They brought flowers with a card for "Roberta."

My grandmother snapped at them. "My name," she said, "is not Roberta."

They were completely confounded but too polite to ask what the hell her name was then.