Close-minded people who always judge Bitcoin as useless and hard to understand.
It is not an obstacle to bitcoin but I think the biggest obstacle for bitcoin is/are the politics that's happening inside and outside of it. If everyone is just united, we're definitely experiencing a greener pasture. Another thing are these news agencies that are spreading fake news and fuds. These things are really obstacles IMO. It stops the market and pressures everyone to sell,mostly the newbies that enforces the market to plunge.