I think one of the factors that can affect the bitcoin price is bad news or FUD's that can holders sell their bitcoin because they think that the price of bitcoin will drop and the other factor is there are some group of a pump and dump that can manipulate the value of bitcoin and the other thing is there are many scammers out there that use bitcoin as their presentation that is why people didn't trust bitcoin because of this reason.
I agree to this thing bitcoins image are being changed because of those people who are spreading a false news of course when people believe that false bews they will look into bitcoins differently and some will panic sell because of that. And those scammers that are using the name of the bitcoins also affect the bitcoins price because as the people believes that those are the real bitcoins of course they will not trust anymore and they will spread also that news and those new comers will sell immediately their holdings.