I once got so claustrophobic just by reading a book about caving that I had to put it away: Blind Descent by James Talbot. It describes the quest of a couple of maniacs to explore the deepest caves on earth under hellish circumstances. No light for weeks, no communication with the surface, camping against vertical walls in the dark, hurricane level winds, tight sumps full of dark water, disease, panic attacks... Man, who in his sane mind does things like that?