Corys are the honest, upright, citizens of the aquarium. They bother no one, eat no one, destroy nothing. They potter around on the bottom of the tank minding their own business and while all-hell can break loose around them they remain calm in a crisis. Any new cory's are welcomed immediately, both large and small. They are gregarious enough to rival Clown loaches and thrive while those said mad-cap stripy beasts do what they do (race around a lot).
I know all this because I have always had cory's and always had Clown loaches.
If people were more like Cory's the world would be a better place -- unfortunately, the world is more like being full of pirhana's or Ghost Knife fish.