The Green Fields of France/Willy McBride parody(if you are taking about the same one as me) is absolutely hilarious in my opinion. And it is not all disrepectful to the song, though it is extremely cruel to some of its singers.
I have had the dubious pleasure of hearing one of my own songs viciously parodied. I can't say I enjoyed the experience at the time but I laughed later. Forty years or so later.