An infectious disease walks into a bar. The bartender says "Hey, we don't serve infectious diseases here!"
The infectious disease says "Well, you're not a very good host."
Two bacteria walk into a bar. The bartender says "Hey, we don't serve bacteria here!"
One bacteria says "That's ok, we work here." "Yeah," says the other, "we're Staph."
A room temperature superconductor walks into a bar. The bartender says "Hey, we don't serve superconductors here!"
The room temperature superconductor leaves without putting up any resistance.