Stand-up comedians, like parents, have a tendency never to give up on a joke. They keep going until it somehow makes someone laugh, even if it's only because of the absurd amount of effort they've put into it.

But there is a difference between someone who thinks they are funny and someone who can consistently produce laughs for a living.

"Anyone can be funny. But the real question is whether you can translate that to a room full of strangers and convince them that you are funny," says Gina Yashere in a scratchy London accent.