Men are more ready to repay an injury than a benefit, because gratitude is a burden and revenge a pleasure
TACITUS, c. A.D. 55-120
The problem is that you often do not know your friends as well as you imagine. Friends often agree on things in order to avoid an argument. They cover up their unpleasant qualities so as to not offend each other. They laugh extra hard at each other’s jokes. Since honesty rarely strengthens friendship, you may never know how a friend truly feels. Friends will say that they love your poetry, adore your music, envy your taste in clothes—maybe they mean it, often they do not.
When you decide to hire a friend, you gradually discover the qualities he or she has kept hidden. Strangely enough, it is your act of kindness that unbalances everything. People want to feel they deserve their good fortune. The receipt of a favor can become oppressive: It means you have been chosen because you are a friend, not necessarily because you are deserving. There is almost a touch of condescension in the act of hiring friends that secretly afflicts them. The injury will come out slowly: A little more honesty, flashes of resentment and envy here and there, and before you know it your friendship fades. The more favors and gifts you supply to revive the friendship, the less gratitude you receive