Almost 30 years after my one and only Carnival Cruise I still have a twinge of guilt over the tip I left my waiter at the end of my week. I didn’t know at the time that waiters relied exclusively, or almost exclusively, on tips from their guests for their livelihoods. My guy was too overbearing for me, and when I gave him an envelope containing maybe half of what he expected he just about chased me off the ship. When I learned why he was so distraught it was too late to do anything about it. Now a new book, Cruise Confidential, brings it all back to me in living color (and then some). USA TODAY travel editor Chris Gray takes a look at it on The Cruise Log blog.