As long as we're quoting Keynes, let's also remember this gem from a letter he wrote to the regents of King's College about the performance of their endowment's portfolio (which Keynes managed).
"The management of stock exchange investments of any kind is a low pursuit, having very little social value and partaking (at its best) of the nature of a game of skill, from which it is a good thing for most members of our Society to be free; whereas the justification of Worlaby and Elsham lies in its being a constructive and socially beneficial enterprise, where we exercise a genuine entrepreneurial function, in which many of our body can be reasonably and usefully interested. I welcome the fact that the Estates Committee-to judge from their poker faces and imperturbable demeanour-do not take either gains or losses from the Stock Exchange too gravely-they are much more depressed or elated (as the case may be) by farming results. But it may be useful and wise nevertheless, to analyse from time to time what is being done and the principles of our policy."
Edit: Worlaby and Elsham was a farm that the endowment owned.