Sed nescio quo modo nihil tam absurde dici potest quod non dicatur ab aliquo philosphorum. (There is nothing so absurd but some philosopher has said it.)
What is morally wrong can never be advantageous, even when it enables you to make some gain that you believe to be to your advantage. The mere act of believing that some wrongful course of action constitutes an advantage is pernicious.
We must be ever on the search for some persons whom we shall love and who will love us in return. If good will and affection are taken away, every joy is taken from life.