Everyone needs to fear hackers. one weird happening was that my friend's fb messenger was hacked and the hacker was trying to chat on us, his close friends and ask for some information bout the online game my friend was playing. we noticed it wasn't him and told him. He checked on his messenger and found nothing of any messages he said and still the hacker continued chatting in his messenger on us. that  was one thing that was very questionable. it was like a ghost that's trying to bother us. well of course this also applies in bitcoin. every field, there are always scammers and hackers, trying to cheat the system. they always find holes in the system or at least trying all necessary means to get everything without leaving a trace.