I can at least understand Clark losing his temper during the "interview" with Lois. It was in privacy, it was late at night, and Clark was probably on edge with the political scandal he accidentally caused.
Superman furiously barging into Luthor's office and demanding Krypto back is another story. For someone who's a reporter in his civilian life, you'd think he would realize this would mean bad press for the Man of Steel.
I really hate to compare this movie to a more beloved adaptation, but here's Superman and Luthor's first major confrontation in Superman: The Animated Series...
https://youtube.com/watch?v=PTfiXcN7-NYAnd here's Superman 2025...
https://youtube.com/watch?v=0LV7y_HnQr4
Also, while it's no "Save Martha!", why does Superman only refer to Krypto as "the dog" in this scene?