The two people who seemingly never got along on The Big Bang Theory were Sheldon and Penny. But surprisingly, they happen to have been the ones who stuck by each other throughout. There were no boundaries of propriety or regard for each other's feelings, they were not constantly with each other and neither did they particularly like each other's presence. Yet, in spite of their apparent mutual dislike, they unexpectedly came to each other's aid, giving people friendship goals in the process. It was one of the most unique relationships on the show, here's why.

1. They're always there for each other, especially when the other ill.

Which is sweet. Sheldon is a hypochondriac who hates falling ill and is very cranky to deal with. She happens to be the only person, after his mother, to have sung 'Soft Kitty' to him. Even though Sheldon keeps stopping her mid-sentence when she does not sing it like his mother does.

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2. They openly point out what annoys them about each other.

Haven't you enjoyed the openness they share with each other? They always bounce back to where they were even after the meanest of come backs.

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3. They try really hard to take an interest in each other's life.

Sheldon does not care two hoots about acting and Physics is like an exotic Middle Eastern animal to Penny. Yet, they do sit and try to understand things about each other's life. Can you imagine Penny playing chess!

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4. They are what '3 AM Friends' is all about.

An annoyed Penny will always open the door to Sheldon's neurotic knocking and a very pissed Sheldon will listen to whatever a drunk Penny has to say. ("Penny!" *knock knock knock*)

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5. They are always just a holler away, literally.

They perpetually have each other's back. Remember when Penny dislocates her arm in the bathroom and Sheldon takes her to the hospital? It was the most un-Sheldon thing he did throughout the series.

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6. Even though they ticked each other off, they lived in complete acceptance.

Penny eats their food, uses their wi-fi, talks loudly while watching a TV show and can be heard across the corridor when she talks on the phone. Sheldon keeps changing the wi-fi password, ("Penny already eats our food she can pay for wi-fi, no spaces") but spills the beans to her in the end anyway.

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7. They always get each other out of a pickle.

When Sheldon is bullied into giving away his 'World of Warcraft' collectible, Penny kicks the guy in the balls and gets it back. Nobody else would have done that for Sheldon. 

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8. They are supportive of each other even to the point of stupidity.

'Penny Blossoms' gets an order of 1000 pieces to be delivered within a day, a business that takes off because of Sheldon's intervention, and Sheldon is completely all game about doing it. In fact the entire business set-up was his idea, starting from the website to the marketing plan.

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9. And because of their differences, they have so much to teach each other

Whether it's the finer details of bathing products, or the implication of the Marvel Universe's latest twist, Penny and Sheldon are always willing to learn from each other. They may not be particularly interested in the other's interests, but they're open to making the effort.

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10. And in their own unique way, they complete each other.

They have no expectations out of each other. Penny never expects Sheldon to help her and Sheldon for his part, does not think Penny is capable of helping him. Yet it happens. Sheldon would never have got his Warcraft sword back, if not for Penny. She on the other hand could never have made a successful business model without Sheldon swooping in.

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These two people came together because Leonard started dating Penny. But each began where the other ended and it can be seen throughout the series. That, right there, is friendship goals.