While meditating, it is not always clear whether you mind is clear of thoughts or not. Some seems to be more emotions or visions. But if all emotions and visions are accompanied with thoughts which are the toughest to recognize that they are there in your mind?
While BonnWarapol's five higher fetters would be the most difficult to eradicate for all non-arahants, for a beginner in meditation, the hardest to eradicate would be the five hindrances (pañca nīvaraṇāni):
- Sensual desire (kāmacchanda)
- Ill-will (vyāpāda)
- Sloth and torpor (thīna-middha)
- Restlessness and remorse (uddhacca-kukkucca)
- Sceptical doubt (vicikicchā)
However, by practice, general practitioners who have never enlightened before, should focus on 5 precepts and catch immoral physical actions, first. Then he should catch 5 kāmaguna-attachment (for jhāna meditation). Then he should catch diṭṭhi vicikicchā and silabataparāmāsa (for access to insight meditation).