There was a very good reason for the 'Wally' shout, it became a custom for quite a while after the Weeley Festival in the early 70's; someone had lost their dog, or their mate or something, and was wandering around shouting 'Wally!', and it just kind of took off.
To my mind, there's good prog and bad prog - all of it played by 'real' musicians, the dividing line seemed to be between those who were just showing off their ability to play widdly-widdly in 17/8 (ELP, Yes, Argent etc) and those who used the musical complexity to try and create something 'other' (King Crimson, earlier Genesis, Hatfield & the North etc). Then of course you had your Brit(-ish) eccentrics who weren't strictly prog, and who had more of a sense of humour or playfulness (Robert Wyatt, Gong, Kevin Ayers, Arthur Brown etc). But, I find that a lot of it doesn't stand the test of time - mostly I find that music from that era that I've never stopped listening to I still love, whereas if you were to put on Camel's 'Snow Goose' I would have to run for cover.