Who should not be befriended according to the philosophy of Islam?

When choosing our friends we should ask ourselves first: Are they going to help us achieve the purpose for which we were brought to life? Or will they take us away from it? Will they desire for us Allah's (SWT) pleasure or is that completely irrelevant to them and not their concern at all? Are they leading us to Paradise or to the Hell?
Imam Muhammad al-Baqir (as) narrates from his father who said, "O my son don't befriend five types of people:
1. Don't befriend a liar (Kadhib). For a liar is like a mirage. He shows the distant as near and the near as distant. He will always deceive you and trouble you.
2. Don't befriend a transgressor (Ghasib). For he will forsake you for a paltry sum and make your sins appear very alluring to you. He will make you a victim of Allah's chastisement through his petty sins and take you farther away from His obedience and satisfaction. He will make Allah's worship appear as His disobedience, and His disobedience as His worship. He will drag you along with himself in the fire of hell.
3. Never befriend a miser (Bakheel/Kanjus). For in your time of need and distress, he will withhold his wealth from you, while he is in a position to assist you. (He values his wealth more than anything else. And to that end he is prepared to forsake even his friends)
4. Do not befriend a fool (Ahmaq). For (in his foolishness) he will harm you while he intends to help you. (That is why it is said, 'A shrewd enemy is better than a foolish friend')
5. Don't befriend the one who breaks relations (with his relatives/Khata Rahmi). For, such a person has been cursed in the Noble Qur'an in three places. He is engrossed in his own affairs with scant regard for others. (Friendship with such a person will eventually lead the individual towards sins and disobedience of Allah)"
Imam Ali ibn Abi Talib (as) said: "Do not befriend a sinner (Fasiq/Fajir) because he will sell you for a morsel."
Imam Sajjad (as) said: "Do not make anyone your enemy even though you consider him harmless and do not turn down a person's friendship even if you think he will not benefit you."
The Noble Qur'an says, "The hypocritical men and the hypocritical women are all alike; they enjoin evil and forbid good and withhold their hands; they have forsaken Allah, so He has forsaken them; surely the hypocrites are the transgressors." (Surah Al-Tawba, 9:67)
On the other hand, Noble Qur'an discusses the believers in the following manner, "And (as for) the believing men and the believing women, they are guardians of each other; they enjoin good and forbid evil and keep up prayer and pay the poor-rate, and obey Allah and His Messenger; (as for) these, Allah will show mercy to them; surely Allah is Mighty, Wise." (Surah Al-Tawba, 9:71)
The two Qur'anic verses mentioned above only go to show how critical a role friendship can play in our lives. A true friend then, is the one who takes us closer to Allah's (SWT) compassion and grace.
Having deliberated at length on who should not be befriended, we shall now see what kind of people should be befriended. Imam Jafar Sadiq (as) narrates, "Friendship entails certain trusts and duties. Then the one who observes these obligations is a true friend and the one who breaches this trust is unworthy of friendship. These obligations are as follows;
1. He should be the same outside as he is inside. In other words, he should not have a dual personality. (In this age however, we often come across people who are exceptionally humble and modest on the outside, with little, if any humility, on the inside)
2. He will consider your virtues as his virtues and your misdeeds as his misdeeds. (In other words your virtues will cheer him and your faults will grieve him. God forbid, he must not feel relieved after observing some vice in you, and take solace from the fact that he himself is above that vice.)
3. If he acquires a position of power and authority, it must not bring about a drastic change in his attitude. In other words, prosperity must not transform the individual adversely. (There are some people who make the best of friends in adversity. But a positive change in their financial condition reveals a dark, hitherto unknown side of their personality. On the other hand we see some people who make good friends in prosperity, but misfortune transforms them, disclosing their fickleness.)
4. He must give his friendship (with you) priority over all his worldly possessions. In other words in times of adversity, he must be willing to give his all to redeem you.
5. He must never leave you alone in times of misfortune and distress."