The lousy mirror.
We have one of those mirrors that magnify your face. My wife calls it the Mirror of Truth and Horror.
I know just what she means!
The sun. It never claims to be day when it's night.
Your eyes....they disclose everything you say
The universe or nature... every time we attempt to inject our biases, they produce an immediate example of our ignorance.
An atomic clock.
Crazy people. Literally crazy, possible mentally unstable.
FORENSICS. People lie, eye-witnesses are wrong, but the foensics tell the exact story, and DNA never lies.