When a man sees something desirable, he must reflect on the fact that with time it could come to involve what is detestable. When he sees something that is beneficial, he should reflect that sooner or later it, too, could come to involve harm.
XunziNow it is human nature to want to eat to ones fill when hungry, to want to warm up when cold, to want to rest when tired. These all are a part of people's emotional nature.
Xunzi