To live among friends is the primary essential of happiness.
William Thomson, Lord Kelvin (1824-1907) Scottish physicist
Lord Kelvin’s Replies to Addresses given on the Celebration of the Jubilee of his Professorship (15-17 Jun 1896)
(Source)
Quoted in G. Fitzgerald, Lord Kelvin, Professor of Natural Philosophy in the University of Glasgow 1846-1899 (1899)