There are good bad ideas and bad good ideas.
A bad good idea would be something like, let's encourage tapioca pudding consumption as a means to ensuring world peace. Not that I ever wrote a song about that in my youth or anything. When you're sixteen you are chock full of bad good ideas.
A good bad idea would be, hmm, it's like a 100 degree day in Portland and our friend is visiting from Toronto, so let's close all the windows and record an extremely loose EP of Buck Owens covers on the boombox. Let's drag out "Dust on Mother's Bible" into a woozy 7 minute space jam with said friend playing just enough on the bass and my dear wife tapping out the faintest of rhythms on the bucket and mixing bowl, let the delay self-oscillation compete with the cassette noise to see what wins.
It's not a good idea - a good idea would have been to head to the river or play in the sprinkler - but a good bad idea is often more memorable than a vanilla good idea.