My first passenger was my father.
He spent the entire flight worrying about being sick (he wasn't, in fact). He wouldn't have done if I'd included the existence and location of the sick bag in my passenger briefing.
This was a 152, so at some point in the flight the passenger door popped open, as they do. This one I got right - I reached across him and closed it, saying "the door is only to keep the draft off, it's the seat belt that stops you falling out".