Well thanks for quantifying normals and almost normals in disparaging terms. Have you conducted a detailed scientific survey to quantify your findings ?
Your anecdote does seem a shade far fetched given steam locomotives, of any class, tend to hiss and puff, clank and burp steam out from everywhere so tend to be easily identifiable as such.
Irrespective of the obsession, for some, as to the type of loco involved, the highlight for many normal pax was....the stock. Compartments were very popular for a generation unfamiliar with them, as was the quality of the seating compared to some TOC's idea of "comfort " . The slam door did cause some slight confusion at times, easily resolved with a bit of humour. Unsurprisingly, kids loved slamming them closed.
DMU's. first, even second, generation and I freely admit I can't tell the difference, if any between the first arrivals and those that followed, are, or should be, a heritage line essential. They were innovative when they first appeared, the all round view being novel, plus, you could see out of the front and watch the driver....assuming the miserable sod didn't close the blinds.