This is a TRUE STORY ... Back about 1957, my brother was a long haul truck driver. He also made extra money by running guns to Castro, who was then a rebel in the Cuban mountains. Once, on his return from a very lucrative gun running trip, he stopped at a greasy spoon, just as you decribed, somewhere in Texas. He had the same waitress you described. After pie and coffe, and feeling thankful to be alive, he left her a $50 dollar tip. He peeked through the windows to see her reaction. You query brought back this true memory.