The Empathy Optimization
While Amy is still away, Sheldon has recovered from the flu, but though his friends attempt to help him, his rude behavior during his illness offends them. They decide to rent a party bus to Las Vegas to get away from him. Amy admits she, too, extended her trip to avoid him, and teaches Sheldon about empathy. After Sheldon realizes what he did was wrong, he apologizes to each of his friends in turn, but his apology to Emily goes wrong when he says dermatologists are not real doctors. When Raj tries to defend Sheldon, it leads to a fight between him and Emily. Sheldon decides not to go to Las Vegas with the group as a gesture of his regret, but sneaks onto the bus with Stuart to make amends with Emily and fix things between her and Raj. Sheldon and Stuart then leave, but the others decide to let Sheldon and Stuart go with them after all.
Title reference: Sheldon trying to feel and understand empathy.