A neutron saunters up to the bar and orders a drink. “How much?” he asks. The bartender says, “For you, no charge.”
A superconductor walks into a bar. The bartender says, “We don’t serve your kind here.” The superconductor leaves without any resistance.
An atom walks into a bar, orders a beer, takes one sip and breaks down in tears. The bartender comes over and says, “Hey pal, what’s the matter?” The atom says, “I think I lost an electron.” Bartender says, “Are you sure?” Atom says, “I’m positive.”
Some helium floats into a bar. The bartender says, “Sorry, we don’t serve noble gases here.” The helium doesn’t react.