1. Wants to keep Big Banks in check and tax them beyond imagination (which inspired me initially) but no way he can possibly enforce that (lobbyist, conflict of interests, and his lack of influence as a congressman)
2. Obviously, he showed he had no courage to go at Hillary when he both had the public supports as he betrayed those who donated millions of dollar via grassroot movement.
3. In California and other States, there has been numerous reports of voting fraud against him and he remained silent.
4. Wikileaks showed he was compromised.

5. Wants to ignore Hillary Emails and server problem (My home country impeached our First woman president due to similiar issue)

6. His reaction to BLM kids rudely taking over his mic and rally and he literally had no clue how to react to that. (Afraid to look like he wants to tarnish Black supports or he is a coward).

7. Free College again

8. No way we can finance all Free University+Illegal Immigration+Health care Plan. Way too bold promise

9. (Personal) I was in my last year of college and realized Free University doesn't mean anything no more lol. Probably would have raised the interets to those with student loans already.

10. No thanks to socialism (Venezuela)

11. Donna Brazile (DNC Official) and others showed colluding with Medias including CNN. HUGE RED FLAG about the state of the party, which relates to my Point #1.

12. Bernie Sanders's lack of accomplishments as a Congressman which is concerning.

13. Lack of endorsements from his fellow senators (despite their "praises") even when he was thriving initially explained the shit show itself.

And I am sure there are few more and I might have omitted some details to above points I mentioned but haven't paid close attention to him as much in last year and half (now I do as it seems he is eyeing 2020 again).