Seneca · On self-control
Letters 116.2
“But,” you object, “it is natural for me to suffer when I am bereaved of a friend; grant some privileges to tears which have the right to flow! It is also natural to be affected by men’s opinions and to be cast down when they are unfavourable; so why should you not allow me such an honourable aversion to bad opinion?”
There is no vice which lacks some plea; there is no vice that at the start is not modest and easily entreated; but afterwards the trouble spreads more widely. If you allow it to begin, you cannot make sure of its ceasing.
Seneca, Letters to Lucilius 116.2, translated by Richard Mott Gummere