Causes of Suffering

Suffering may arise from

1. Attachment
2. Expectation
3. Judgement

Attachment to things which are not permanent and or are changing/volatite. This may include objects, desires, people, events, outcomes, and even the physical body.
To further extend this, suffering may be caused to an attached idea or expectation which has not yet being determined (e.g. worrying about something that may happen/not happen in the future). Alternatively it could be something hung up on from the past, and cannot be let go of (e.g. something that happened and you blame yourself for it). Present suffering is the pain experience at the present moment. e.g. when you break a leg. Note that all these forms of suffering are caused by attachment to impermanent things. Ofcourse to achieve absolute detachment is relatively impossible, however attachments can always be reduced.
Expectation arises from wanting things to be in a certain way, i.e. whether you expect people to act and behave in certain ways, or events to proceed in a certain fashion, or anything of that nature.
Judgement is usually derived from expectation and is due to a certain expectation not being met. One's judgement of others surprisingly outweighs one's judgment of the self, unless the inidividual becomes more self-aware.
Judgement is an act which can only be done by the one who has absolute knowledge on all aspects and history of what is being judged, which is virtually impossible for any individual to possess such a quality.
Judgement however tends to be necessary for the sake of law and order, however it should not be extended beyound this.