Heck, even as a daily cigar smoker, I've had this happen on many occasions, though not so much any more. I had a Cusano Corojo lay me out flat for a couple hours once. They're sneaky little devils--all nice and buttery tasting until you realize you've been smoking the equivalent of battery acid. Truthfully, though, I think it depends upon the occasion--empty stomach, tired, not used to heavy blends, etc.