To waylandsmithy: (a true story - is that allowed here?)
In order to get elected, the late Clement Freud, former MP, admitted that he used to quite cynically scan the local paper and make a point of writing an appropriate personal letter to anyone in his constituency who had given birth, won an award, had a notable birthday, been bereaved etc.
Worked fine except that when constituents came up to him at meetings and said "Thank you so much for your letter, I realy appreciated the thought" he was unsure how to respond, not having the faintest idea whether it had been, say, a bereavement or a golden wedding aanniversary.
Eventually he hit on the idea of always replying "It was the least I could do ..."
Genius. He deserved to get elected for sheer chutzpah.