Conservation at its best.
Sorry if I offend anyone with this joke, but it needs to be said.
So this Positronium couple walks into a bar, and as they walk in a Photon walks out.
As the Photon leaves, the bartender, being a conservative guy, yells:
“Hey! You forgot your Neutrino!”.
To which the Photon replies:
“What am I? A Muon?”
