Republic 329d2-4

But, indeed, about these things and the things concerning relatives there is one cause, not old age, Socrates, but the character of human beings.

[Nearing the end of Cephalus's speech on old age. The comment about relatives refers to Cephalus's earlier statement that some of his old friends "bewail the abuse of old people from relatives. . ."

Note that in some ways C.'s diagnosis of why people are disgruntled in old age is similar to Socrates's (see book 4, 441c and following), though S. and C. will disagree about the benefit of money.]