People jumping out and going “boo” is absolutely counter to the lyrical effect Pier was trying to achieve.  The centerpiece of the whole affair is a distant mournful violinist, for gosh sakes.
Maybe it has something to do with how long one has attended.  I’ve been to 14 events, and I don’t remember a single specific scare - they blend together.  I DO remember sets, gags, puppets, costumes, tone, sfx, etc.  Apropos of nothing, I agree with Darko that the event was at a height from 17 to 19, though I preferred 18 very slightly to 17.
This is a very, very interesting year because, despite an all-time house and strong streets, everyone agrees something is off but no one quite knows what that is.  I share the sense that SOMETHING just didn’t gel - a preponderance of mediocre houses?  A lack of variety?  The absence of a strong creative voice outside of Pier and perhaps Monsters? I don’t know what it is.  The several years following 21 were simply weak events, the problems were clear.  I wouldn’t call 31 weak, just odd.  Perhaps it’s the product of settling into a new era of the event, but if that’s it, I can’t quite see the shape of HHNs to come just yet.