Final answer:
When encountering someone you know in public, greet them warmly and introduce yourself, regardless of their age. Rude or disrespectful behavior, such as ignoring or making fun of someone, should be avoided.
Step-by-step explanation:
When encountering someone you know in public, it is generally considered polite to greet them warmly and introduce yourself, regardless of their age. This applies to passing acquaintances in places like school, work, or the grocery store. Ignoring or laughing and making fun of someone are considered rude and disrespectful behaviors.
Rules of behavior may differ based on cultural norms, but in the United States, personal space is highly valued and physical contact should generally be avoided unless there is a pre-existing close relationship.
Remember, it is important to treat others with kindness and respect, regardless of their appearance or difference.