Yeah, that was why I got a little tired of it. It would seem to me that if detectives were really operating that way, they would find the lie, and then work backwards to find proof of it. Just explaining why certain micro expressions mean "you're lying" should not be enough to solve the crime. It would be enough to know the truth, and know what they should be looking for.
There was an episode about a politician who had been visiting a call girl. They caught him in his lie, and he admitted what he had done, but explained that he wasn't actually doing anything but talking, and he was spending time with her because she was his daughter whom he never knew, and he hadn't told her yet. That guy was decent, and it made sense for him to tell the truth, because he wasn't really doing anything wrong. But the criminals? The cops saying "I know you're lying" is not enough to make them tell the truth, so how is Tim Roth saying it going to make it happen?
I would also find it more interesting if he were wrong once in a while. That's one thing I like about HOUSE MD. He's brilliant, but he's sometimes wrong.
I also thought there was zero chemistry between Roth and the female lead, and I was completely uninterested in that whole subplot, and it got boring.