I've never heard of people who have had these problems but I can definitely see where there coming from. I think dissociation and unwanted false awakenings would be the major ones. I had 4 false awakenings in a row one time and on the 4th one I started wondering if I had died but that thought woke me up to the real world. I also read in Lucid Dreaming: Gateway to the Inner Self that Robert Waggoner had 11 false awakenings in a row. Now that would be a trip. Waking up the 7 - 10th time I'd be like fuck is this really happening.