But pleasures can never be so multiplied or continued as not to leave much of life unemployed
 Samuel Johnson, The History of Rasselas, Prince of Abissinia (1759). copy citation

Context

“but considering himself as master of a secret stock of happiness, which he could only enjoy by concealing it, he affected to be busy in all the schemes of diversion, and endeavoured to make others pleased with the state of which he himself was weary. But pleasures can never be so multiplied or continued as not to leave much of life unemployed; there were many hours, both of the night and day, which he could spend without suspicion in solitary thought. The load of life was much lightened; he went eagerly into the assemblies, because he supposed the frequency of his presence necessary to the success of his purposes;” source