Bubba is slang for a redneck/hillbilly of generally low intelligence known for making repairs to automobiles that do more harm than good.
Yes. I use the term generically to indicate whoever did the poor work that I am currently fighting with. Depensing what vehicle I am working on, sometimes Bubba was teenage me.
I explained it to my kids as a way to ascribe frustration to a personification without any actual blame being applied or attacking any real person.
That explanation might indicate that I have spent way too much time thinking about this.