I watched Man About the House when it was first on, but at the time I missed a very naughty in-joke in the closing credits. I must have caught a repeat years later when it hit me in the face, so to speak.
For those who don't know (practically everybody, probably!) the comedic situation was that a hot-blooded young chap shared a flat with two dolly birds, to use the sexist parlance of the era. Regrettably I can't find the particular image but the gist of the closing credits was that we'd see a series of images depicting one masculine personal or household item juxtaposed with two feminine items. The image I spotted in the closing credits some years later was of three ornate porcelain ornaments: one cockerel, and two cats...
(Oo-er, Mrs, I've just found it!
Play video from here. The very last frame before the Thames logo.)