Mycroft brings up past grievances and Sherlock's weak point: Mummy.
Guilt Trip
Sherlock's eyes were on the new barista who had taken the place of his comfort-zone favorite.
"Want me to put surveillance on him?" questioned Mycroft, guessing that this was the new barista who was making Sherlock more irritated than normal.
Sherlock looked at him in disgust, almond-shaped eyes narrowing. "I'm not entirely sure why you're here, Mycroft."
"Just inviting you home for the weekend. Mummy would love to see you."
"I'd like to see her too, but not with you around."
"You'll make her cry."
The insult hit Sherlock's ego with a satisfying smack. "Fine. Just a day."
Prompt was #74: almond