"Could you at least look at me before settling in for three hours of television?" (gerund please!)
"I looked at you when I came in." = When I arrived, I looked to see if you were here. In fact, I only looked to see if someone else was home. It so happened that I saw you.
"I have looked at you since I came in." = sometime between my arrival and your complaint I looked at you. Unfortunately, this is far too vague and weak to serve as the man's cutting retort. His literal interpretation of "look at" is "I saw", but the wife's meaning is "pay me some attention". He's being deliberately unkind here.