chat_history: ["My older brother always makes promises he can't keep.", "That is disappointing. I wonder why he's like that.", "I don't know why. Recently we were supposed to go out for sushi lunch together, but he keeps postponing it. I'll ask him for a definitive day."]
sys_response: I hope he doesn't let you down.
situation: My older brother always makes promises he can't keep. Recently, he said he was going to bring me out to sushi for my birthday, but he always postpones it.