Hi John,
I was looking at it from the wrong angle, I was thinking "Shock" only in a scandalous way (sexuality, sensible topics) and forgot about the power of colours & techniques.
I can understand why painters were shocked when Renoir & Monet walked down the street with their impressionist canvas (Damn youngsters!).
Like you said, people were not used to vivid colours, it must have been a fantastic eye-opener.
Nevertheless, classic & academic run of the mill is still captivating, even if nobody has been shocked in a while (some Carravagios makes me feel uncomfortable tho)
Hard to imagine how people felt when they saw a daguerreotype, attended a cinématographe projection or heard music coming out of a phonograph for the first time.
I'm envious, those are the kind of things that we rarely experience these days.