On the top of my head, here's a few.
- Misinformation/Misunderstandings: There are so much misinformation spreading about bitcoin. Namely, "bitcoin is not scarce, people can create forks", "bitcoin is only used for drugs", and many more. There's so much misunderstandings of people in social media and on television; and what's worse, is that they're spreading their misinformation! Causing a sort of domino effect on people's impressions of bitcoin.
In my view, I think Misinformation is the main obstacle of bitcoin. In our country, If random people know that someone is working for bitcoin, then they can complain to the Cop! Because most of them think that Bitcoin is illegal, It is only used in bad works like drugs, murder and so on in a negative way! Therefore bitcoin has the volatility nature, the price can be manipulated any time, it is one of the obstacles.