The following is an excerpt from Patience and Gratitude by Ibn Qayyim al-Jawziyyah, a book I highly recommend everyone should read:
Psychologically speaking, every person has two forces at work within him or her. One is the “driving force”, which pushes him towards some actions, and the other is the “restraining force”, which holds him back from others.
Patience essentially harnesses the driving force to push us towards good things, and the restraining force to hold us back from actions that may be harmful to ourselves or others. Some people have strong patience when it comes to doing what is good for them, but their patience is weak with regard to restraint from harmful actions, so we may find that a person has enough patience to perform acts of worship (Salâh, Sawm, Hajj) but has no patience in controlling himself and refraining from following his whims and desires, and in this way he may commit harâm deeds. Conversely, some people may have strong patience in abstaining from forbidden deeds, but their patience in obeying commandments and performing ‘ibâdah is too weak. Some people have no patience in either case! And, needless to say, the best people are those who possess both types of patience.
So, a man may have plenty of patience when it comes to standing all night in prayer, and enduring whatever conditions of heat or cold may be prevalent, but have no patience at all when it comes to lowering his gaze and refraining from looking at women. Another may have no problem controlling his gaze, but he lacks the patience which would make him enjoin the good and forbid the evil, and he is so weak and helpless that he cannot strive against the kuffâr and mushrikûn. Most people will be lacking in patience in any one case, and a few lack it in all cases.
A scholar said: “To have patience means that one’s common sense and religious motives are stronger than one’s whims and desires.” It is natural for people to have an inclination towards their desires, but common sense and the religious motive should limit that inclination. The two forces are at war: sometimes reason and religion win, and sometimes whims and desires prevail. The battlefield is the heart of man.