I was listening to a psychologist on the radio with my son a few months ago and I said I'd look up his books - and now I can't remember who he was.
He had re-worked a book he originally released 10 years ago. He talked a bit about how continually striving for happiness was unrealistic and unhelpful. He was English. I'd say around 40ish, as he was taking about his son who was in his early teens.
Does anyone have any suggestions about who it was?