Tried to fix my own leak with generic plumber's putty, but the $8 tube of specific pipe thread sealant from the hardware store was the only thing that actually held.
After the putty failed twice in my kitchen sink and caused another small flood, I learned that using the exact material meant for the job, even if it costs a bit more, beats trying to make a general product work every single time, so what's your go-to fix for a stubborn threaded joint leak?