My aunt always served tea before asking questions. It was not a rule she announced, just a pattern she kept. When I arrived that afternoon, she placed two mugs on the table without asking what I wanted. The tea was chamomile. I knew because the smell carried before the steam settled.
Chamomile is commonly used for mild relaxation and sleep support, largely due to flavonoids that interact with certain receptors in the brain (McKay and Blumberg). She did not explain that. She did not need to. Family knowledge often works that way—passed through repetition instead of instruction.