Why is Leonard friends with Sheldon?

I can't believe it's taken until The Big Bang Theory Season 7 Episode 7 for someone to ask Leonard that question. And, surprisingly, it didn't take Leonard long to answer.

He realizes that Sheldon often is not an easy person to be around, but his quirks are worth it.

When Sheldon's childhood idol, Dr.  Jeffries, selected Leonard to help him with a project, Sheldon's competitive and possessive side went into overdrive. His irritation at being passed over made sense, but so did Dr. Jeffries' reasons for not wanting to work with Sheldon.

Sheldon's just not an easy person to be around. And, when science and his intellect are involved Sheldon can be down right intolerable. In and intriguing twist, Sheldon sort of acknowledged that he could be annoying. His rant with Amy was hilarious with his continual repetition of "I'm annoying" proving his point. 

He's not one to let anything go though. In order to overcome the slight, Sheldon brought Dr. Jeffries nemesis to the University, Bill Nye the Science Guy. The confrontation between the two television scientists was funny to witness. I give the win to Dr. Jeffries who refused Bill Nye from getting a good look at their project.

Plus, Bill Nye was stuck having smoothies with Sheldon. Dr. Jeffries was much better off back in the lab with Leonard. The smoothie trip didn't end well, as Sheldon shared, "I've been informed that he's now Bill Nye the Restraining Order Guy."

Leonard's support of his friendship with Sheldon provided Dr. Jeffries with a different perspective. And, Dr. Jeffries showed up at the apartment to ask for Sheldon's thoughts on his scientific paper. It was a touching moment, which was followed up by some creepy, yet hilarious ogling of Penny. 

While Leonard and Sheldon were working through their Dr. Jeffries issue, Raj was dealing with his overbearing friend, Howard. Those two have always had a very close bond. Raj doesn't have a strong record of standing up for himself, but he did here and it was awesome to see.

Raj's overlapping interests with the gals has been a continual joke on him. Finally, he stood up for his interests when Howard's presence took away his safe haven. The girls accept Raj and let him be himself without the fear of ridicule. Howard took that away when he joined jewelry night.

They resolved their issue without much trouble and Raj even make Howard a gift. A light saber belt buckle. I lost it when Raj demonstrated how they could duel with them. "You can wear yours and we can have little sword fights whenever we want," oh, yes, you can!

Overall, "The Proton Displacement" had plenty of touching and funny moments. The return of Bob Newhart and the appearance by Bill Nye both were highlights of the hour. It may have been stunt casting for ratings, but their use in the episode was well written and worked.

Check out some of the funniest lines in our The Big Bang Theory quotes section.

Carla Day is a staff writer for TV Fanatic. Follow her on Twitter and on Google+.