CBS is all about dramas, and I watch them all. The best one, though, is the under-appreciated “The Unit,” the military drama, co-created by the illustrious David Mamet and Shawn Ryan (“The Shield”). The show, which moved to Sundays at 10 p.m. for its fourth season, features a fast-paced storytelling style, great action, exceptional writing and acting, and top-notch casting. The Feb. 15 episode, “The Last Nazi,” written by Mamet, is an Emmy-worthy example of how good TV can be. Mamet blended taut suspense and great dialogue as he balanced several storylines that included a Presidential order to capture a Nazi war criminal and Col. Ryan’s (Robert Patrick) confrontation with his past as he ponders a promotion to Brigadier General. Watch it.