Opionion # 1: John Stuart Mill, Essay on Utilitarianism

The happiness which they meant was not a life of rapture, but moments of such, in an existence made up of few and transitory pains, many and various pleasures, with a decided predominance of the active over the passive, and having as the foundation of the whole not to expect more from life than it is capable of bestowing. A life thus composd, to those who have been fortunate enough to obtain it, has always appeared worthy of the name of happiness. And such an existence is now the lot of many during some considerable portion of their lives. The present wretched education and wretched social arrangements are the only real hindrance to its being attainable by almost all....

When people who are tolerably fortunate in their outward lot do not find in life sufficient enjoyment to make it valuable to them, the cause generally is caring for nobody but themselves.... Next to selfishness, the principal cause which makes life unsatisfactory is want of mental cultivation. A cultivated mind --- I do not mean that of a philosopher, but any mind to which the fountains of knowledge have been opened, and which has been taught, in any tolerable degree, to exercise its faculties --- finds sources of inexhaustible interest in all that surrounds it....