Today, I learned a metaphor that would explain the leechi-ness and glue-like characteristics of some people. I am talking about pachyderms who go for free rides at the expense of others. Riding the gravy train is very much akin to parasitism plus insensitivity.
"To ride the gravy train" means to secure an ongoing situation that provides good pay or other benefits with little labor or trouble, the equivalent of "living on Easy Street." It may be that the phrase originated among hoboes and other vagabonds who hopped trains as a way of life and for whom "gravy train" would be a likely metaphor for an easy existence.
Just as in avoiding the drama queens, there is a way to rebuff these unwanted free-riders of the universe. Don't give them a hoot. Deworm your life. Watch your money like a hawk:).