2. We laughed when Leonard and Penny tried to move across the hall
It's relatively normal for married couples to live together... alone... without the presence of a roommate. However, when Leonard and Penny voiced interest in cohabitating after tying the knot, this was not a move Sheldon accepted easily.
Instead, the theoretical physicist was understandably afraid to be alone and lose his friends, which is why his sad and snarky protests pulled at our heartstrings. But, we weren't the only ones impacted. After much duress, both Leonard and Penny struck a deal with Sheldon, agreeing to take turns staying the night at his apartment until he could handle living on his own.
Now, that's true friendship.