The reason Marlene loved milkshakes so much was not just because of their creamy deliciousness, but because when she was seven and her sister was born, she was no longer the baby of the family. Her little sister was showered with love and presents and Marlene felt jealous and neglected.
Marlene’s father, Mitchell, noticed this and took Marlene out to talk to her about how her life would change now that there was a new baby in the house. He took her to an ordinary muggle ice cream parlor and ordered two vanilla milkshakes.
Since that night, Marlene has always associated milkshakes with the love her father showed her, and the bond between them.