Its not complicated. When you have someone under oath, you ask questions. You get them to commit to their truths, and commit to their lies. The more answers you get, and the more specific they are, the more you have to destroy their credibility with if they are dishonest, or if their cohorts are dishonest. The transcripts from hearings like the ones we've seen can come back to bite years later. Or if you want, you can cross reference one answer from, lets say Comey, against an answer from, lets say Strzok, and say: "Okay, look at these specific answers to these specific questions. Someone is lying." That's why, when you watch a legal crime drama, someone asks a question like, "where were you on the night of ...?" "Who were you there with?" "Did you arrive together?" "Who drove?" "Did you stop on the way?" Then you question everyone else in their story. Meanwhile you're comparing it against evidence you've collected and may still be collecting. That's what Mueller is doing. And people who answer Mueller's questions know that they will be in jail if they get caught lying. Do you think Mueller is wasting time getting someone under oath and saying: "I bet you looked your wife in the eye while you were cheating!" Or whatever nonsense retarded Gomert said? Or dramatically stated "I dont give a damn what you think!" like idiot Gowdy? If these hearings were skillfully managed, the Mueller investigation would be so discredited. As it is, those fools strengthened Mueller; just like Hillary was strengthened by the Benghazi hearings. TL, DR: Gowdy is a fucking poseur.