I received a lovely email on my work mail today (I'm a teacher at a secondary school).
It was from someone saying they sat their GCSEs with me in 2014 and that they are now at uni and it was a long email about how grateful they were for all my help and support during their darkest days.
I know it's awful but the name isn't ringing any bells 
I feel like I should have been "oh hi X! Great to hear from you" and meant it. I haven't responded yet, unsure if I'm even allowed to. This has never happened 