I think when it comes down to it, the main thing is the "renewal" of the mind. Before being born again, your mind is programmed of worldly things. Now when you are born again, remember, it's only your Spirit that is new, not the mind. It's the person's job to re-program their mindset. If their mindset is still thinking worldy things, if they are not training, if they are not meditating on the Word, the mind will tell them being a Christian is "difficult".