In my opinion, sections I find frustrating are of an often unnecessary length (GPS to get to the end) which also inevitably causes lengthy queues and also complexity of markers often where there are upto 4 routes through one section (usually created by blind panic out of control which way do i go, is that a yellow or green marker). Bottlenecks are inevitable in any trial but when its every section it becomes a joke and does unfortunately remove some of the pleasure.
I've done my share of CofC, "luckily" when all trials had 1 route.....! (showing my age now!!)
Andy