least favorite thing bitcoin is the lack of marketing and public awareness it. due to with it is still believed by many be a geek thing, simple or people who are not in the web world much don't want to get into bitcoin world.
Thats true, lake of marketing and advertising is a big reason why bitcoin is not yet as much popular as it should have been, because the ones who are not involved with the things like online earnings or etc would never come to know about it unless they see an advertisement of it or someone tells them personally.
But who will take initiative of marketing and promoting bitcoins to the world as everyone is busy in collecting their own coins and do not bother about anything else.