“Aren’t you going to share or offer to share?”

Three of us went to a local popular restaurant to celebrate his 18th birthday. This restaurant is known for giving free dessert for birthday celebrant. A team of waiters and waitresses sang happy birthday to him, and presented him a small plate with dessert. I do not like sweets, but I was waiting patiently, and hoping that he would offer to share. I did not see any sign. Finally, I had to verbalize my dissatisfaction and said “ are you not going to share with your mom, or at least show a small gesture?”