House

When House and Wilson are at the bar, after House hangs up the phone call with his team, there is a pen placed on top of a napkin next to Wilson's drink. By the time that Wilson takes out his wallet to pay and leave, the pen makes its way away from the napkin and next to the empty peanut bowl.

When the team (plus Cameron and Chase) are talking after diagnosing House with syphilis (from the fake blood sample), Chase asks Cameron if she slept with House and then becomes upset when she doesn't answer. He should have known the answer to that question. At the end of "Half-Wit," Cameron, Chase and Foreman come to House's apartment to tell him that he doesn't have brain cancer, he has syphilis (again from a fake blood sample). Cameron states that she is glad they never slept together.

House's team claims that House turned into a jerk because of his leg, Foreman then states it was just a coincidence. However, in the season 1 episode "Honeymoon," Stacy Warner (House's ex-girlfriend) reveals that he was pretty much the same way before his leg affected his life.

After bowling his second strike, Chase turns around to notice House has disappeared. The machine can be seen resetting three pins, yet as Chase had just bowled a strike, it should have set down a full rack of pins.

Kutner and the others suspect that Deb gave Jeff syphilis, but they don't take the simple step of testing her to see if she has it. Also, if they believe that Jeff has syphilis and treat him for it, then the next logical step would have been to prescribe treatment for her as well, since she was his wife of ten years.