What are the reasons that lead to the fabrication of Hadith?

A fabricated report is speech that is invented and falsely attributed to the Messenger of Allah, peace and blessings be upon him. Some scholars have gone so far as to say that the one who intentionally fabricates a hadith commits an act of disbelief, though the more prevalent view is that it is a major sin. The reasons for fabrication are numerous, including: corrupting the religion, supporting a particular opinion or school of thought, seeking worldly gain, seeking proximity to kings and rulers, and encouraging people towards Sufism.