Interesting, I don't usually think in demonic terms, for example in this case I just chalk it up to not having enough will power, control, experience, etc., to just sit down and click right into meditation, sure the underlying cause might be demonic, but those thoughts seem to be demolished as soon as I realize it's me that needs to improve with God's help. In other words, I know it's possible and I should be able to do it, regardless of the reason.
Spirit image, I agree with what you say but I have been looking back often, I've been meditating for 36 years now sometimes imposing upon my self a harsh and continuos discipline, but restlessness has never left me. The only explanation I find is that a demon is trying his best to frustrate my effort. Of course the demon makes use of karma and enhances the negative karmic influences which in my case would enhance the natural restlessness. of the mind. I can feel the malevolent intelligence behind it.
The advantage of noticing this is that it becomes a personal issue. That is, not giving satisfaction to that demon becomes a priority, so meditation becomes a double priority.