I'm writing this post while in the middle of arranging a song destined to be part of a barbershop contest package. So I am thinking very specifically about the craft of producing contest-grade barbershop, though I suspect I may find myself ranging more widely by the time I'm done. It is very much writing-to-figure-out-exactly-what-this-thought-I-am-trying-to-have mode, so I may ramble. You have been warned.
(Of course, if the thought ends up being especially trite, I have the option of never posting it. Though I might enjoy the irony of engaging in deep thought to come up with a truism. That in itself might say something about the subject.)
So, 'hack' is the phrase used in stand-up comedy for material on themes that are over-used. It is an insult that includes both lack of creativity (you couldn't think of anything original to say) and laziness (you came up with the most obvious joke, then stopped working). The term is, I imagine, derived from 'hackneyed' in the more general sense, as tired and clichéd, but there is a specificity to its usage in comedy that I find interesting.