He wasn't sure he wanted to live in the same house as Doctor Sheldon Cooper, after the crazy things he had seen.
Sure, he offered a good room at a good price. Living with him was surely the best decision, so he went to the house and he knocked at the door.
Sheldon himself opened the door.
"Can I help you?"
"Hi, I'm here to see the room." Said Leonard, insecure. "My name is Leonard Hofstadter."
"Leonard, really?" Squeaked Sheldon. "Like Leonard Nimoy!"
In that moment, Leonard understood there wasn't a person but Sheldon he could think of living with.