Or....

I had a click in my left pedal (I thought) on my old road bike that I just could not figure out. Checked the pedal bearings, the bottom bracket bearings, looked for a rock stuck in the shoe's cleat mounting channels, nothing.

Then I got a new bike this spring, new pedals, new shoes and everything and... the click was still there.

It's my knee

No pain, no perceptible shift in the joint, just the noise. What mechanics refer to as a "non-harmful noise."