I like the back and forth between QA and Dev with regards to whether or not a bug is worthy of their time to fix and that is the central theme to my favorite bug.
We had an app that was getting blown up by a few different fonts. When dev pushed back, I had my team use the new font that our company had came out with when our corporation had a re-branding effort a few months prior.
The new “official font” of the company caused the app to crash as well.
Development then decided to fix the bug.
-- James W. 

Do you have a bug whose story you love to tell? Let me know!