Hours wasted practicing and rehearsing. More hours wasted spiffing up a uniform that was otherwise never worn. More hours wasted standing around waiting for instructions. Hours taken away from much more useful work and activities.
A retirement or change-of-command ceremony was bad enough, but a parade was at least 10x worse.
(At least at the last retirement ceremony I had to attend had a little levity...it was the mid-70's, and we were all standing at attention in the parade field when they started the music. One of the selections was "The Liberty Bell March". Think about it for just one second - it's the late 70's, a bunch of mostly 17 to 20-somethings all standing at attention, when the Monty Python theme music starts. You could see the shoulders heaving as half the troops tried to suppress laughter. A few were unsuccessful at suppression. All the while, the older folks with scrambled eggs on their hat brims on the reviewing stand are wondering what the hell was going on in the ranks to elicit such a reaction. Priceless! I think that the majority of us were all hoping for a giant foot to come down from the sky to put a final point on the event.)