My reasons:
1. Travelgate, where she had false criminal charges filed against loyal dedicated career government employees.. so she could give jobs to her Arkansas cronies
http://en.wikipedia.org/wiki/Travelgate
2. Being like her husband Bill Clinton in always looking to the political winds to decide how to vote --not just doing what was right
3. Her fence sitting on important issues such as drivers licenses for illegal aliens
4. Her failed health care initiative while First Lady
5. Her continued belief in big government socialized medicine
6. All of her alleged campaign finance violations, including alleged false FEC filings
http://en.wikipedia.org/wiki/Peter_F._Paul
7. Her complicity in Bill's abuse of power and efforts to destroy critics and deny fair trials to women
..and many other reasons.
Hillary is the worst political candidate EVER.