It's interesting that you mentioned Mannix. I remember my first job, at a bowling alley in Chicago, a couple of years before I got interested in old TV sets. It was 1978, and my family had still never had a color TV set, so I knew little about them. I saw the TV on in the bowling alley's bar, and a Mannix rerun was starting, so I stopped and watched for a couple of minutes. It was a color TV. That was the first time I noticed-the picture tube was obviously ROUND! It just seemed weird.
I still love the opening credits of that show.