First Type :

Fail to find God by observation, conclude that there is no God and that this world of wonders made itself, or existed from everlasting.

Second Type :

Through ignorance of the real nature of the soul, repudiate the doctrine of future life, in which man will be called to account and be rewarded or punished

Third Type :

Believe in God and a future life but with a weak belief. Their state of mind is like that of a sick man who, when prescribed a certain regime by his doctor, should say, “Well, if I follow it or don’t follow it, what does it matter to the doctor?” It certainly does not matter to the doctor , but the patient may destr0y himself by his disobedience.

Fourth Type :

Those who say, “The law tells us to abstain from anger, lust and hypocrisy”. These people ignore the fact that the law does not tell us to uproot these passions but to restrain them within due limits, so that by avoiding the greater sins, we may obtain forgiveness of the smaller ones.

Fifth Type :

Lay stress on the beneficence of God, and ignore his justice, saying to themselves, “Well, whatever we do, God is merciful.” Although the Quran says, “Every living creature’s support comes from God” (11:6), it is also written, “Man obtains nothing except by striving.”

Sixth Type :

Claim to have reached such a degree of sanctity that sin cannot affect them. Yet, if you treat one of them with disrespect, he will bear a grudge against you for years, and if one of them be deprived of a morsel of food which he thinks his due, the whole world will appear dark and narrow to him

Source: Kimiya e saadat(Alchemy of Happiness), pg 26-29, Al-Ghazali