As you get older, you need to make more of an effort to appear wise to substitute for failing powers of memory, concentration, etc. Hence my reliance on pithy quotes.
I often (deliberately) misquote JFK, who said:
Happiness is the full use of your powers along lines of excellence.
I modify it to get to the spirit of what I think he meant by substituting "along lines of excellence" with "towards noble ends". To misquote someone else, excellence in the pursuit of vice is no virtue.
I have an opportunity to trot this phrase out about twice a year, usually without attributing it unless asked. Another secret revealed.