Sheldon had really been putting forth an effort to be polite.

Leonard's new girl was actually quite likeable, as far as Leonard's girls went – intelligent, polite, with a seemingly limited interest in the mundane topics girls typically liked to discuss. She was blonde and tall, and her name was Jenny, which tempted Sheldon to psychoanalyze Leonard's motives, but he had kept his mouth shut. It was rare that Leonard brought home girls that Sheldon could tolerate, so he would try his best to be accommodating.

It had all been going splendidly when Jenny plopped into the one place she never should have plopped. Sheldon froze as Jenny settled into his spot, and tried desperately to squelch the feelings of outrage and panic that started to rise within him. He could see Leonard gesturing wildly at her out of the corner of his eye.

Jenny stared at Leonard in confusion. "What are you…"

Sheldon stated, calmly, "You can't sit there."

A look of comprehension and slight horror dawned on Jenny's face, and she immediately sprang off the cushion. "Oh, I'm so sorry, Sheldon! Leonard told me you…um…liked things a certain way and had your own spot, but I forgot."

A calm settled over Sheldon as she exited his seat, and he was all set to offer a generous and rare assurance of "No harm done" when she settled in the cushion next to his. He froze. That feeling of outrage rose up again.

Something wasn't right about this, but he couldn't pinpoint why.

He stared at her, eye twitching, flingers clinching. Why was he upset about her sitting in that spot? It wasn't his spot. But every cell in his body was protesting that it wasn't her spot either.

Leonard was eyeing him warily. "Sheldon? What's wrong now?"

Sheldon sputtered a moment while he stared at the wrong person sitting in that spot. The wrong color blonde, the wrong face, the wrong name. "You…you can't sit there, either."

"What?" Leonard protested. "Why? That's not your spot! When did you start caring about that spot?"

Sheldon swallowed, just as panicked and slightly outraged by his current realization as he had been over the offense.

"That's Penny's spot."

For the rest of the day, Leonard had this weird feeling that reality had shifted.