I saw my hermes delivery lady while shopping today, she's lovely, I so nearly said hi to her, then remembered she's only my delivery lady. She is a star.
i'm sure she'd be delighted if you said hello loujareth but i know what you mean - i saw my dental nurse in asda (who i adore, unlike the dentist) and was going to say hello but changed my mind. actually, in truth i was going to say 'he tortured me while you were on holiday!' lol!!