Yesterday I was sat working when a woman came up to the reception desk I was at and was waiting there. I looked at her, turned round to my colleague 'cos I was busy at the time and said something like "please would you help this woman out?"
My colleague gave me a really funny look and then I looked back at the woman at the desk and realised it was someone I work with (and someone I see a fair bit of so have no justifiable excuse for not recognising).
It was genuinely one of the most embarrasingly blatant failures to recognise someone I've ever had in my life and, although she found it funny, I think she was kind of offended.
Anyone else ever do anything similar? If you did it'd probably make me feel better...