The finale of season 7 of The Big Bang Theory left viewers gasping for answers with regard many obstacles that seem to have fallen in the gang’s way. In reality the future of the main cast is also uncertain as their contract negotiations continue to be disputed. What is certain about this hit comedy, however, is it popularity. Here we look at the seven reasons, for seven seasons, why it's such a firm favourite with viewers worldwide.

Big Bang TheoryJim Parsons character [bottom left], Sheldon Cooper, is a big reason why The Big Bang Theory is so popular

Sheldon Cooper

The stand out character of the show is Sheldon Cooper. Uncompromising in his ways, unchecked in his conversation and in no doubt of his own brilliance, Sheldon is a fantastic character in so many ways that have never been explored in a TV series before.

If it was just The Sheldon Cooper Theory, that show would still be worth watching.

Penny

We might not even know her last name but Penny represents a bigger scope of the viewing population than any of us may care to admit. She doesn't understand the majority of what her 'clever' friends are talking about and, despite all her good acting intentions, her lifelong dream still alludes her.

She may be baffled and unfulfilled most of the time but that's exactly what makes her a woman of the people.

More: Is the cast of The Big Bang Theory worth $1million per episode?

Big Bang TheoryThe cast of the Big Bang Theory

Relationships

Sheldon Cooper with a girlfriend was a tricky subject to tackle but the introduction of Amy was executed perfectly. His character compromised nothing of what makes him brilliant and Amy as a person in her own right is "It's a tiara!!" fantastic.

Leonard and Penny and their on again off again relationship has been a firm staple of the show that everyone can get behind. She makes him cooler and he makes her smarter. And finally, after season 7's latest developments, can we really see a light at the end of the on again tunnel?

Next page: the girls of 'The Big Bang Theory'