What strikes me the most about the entire thing is that most of the people who are going to end up in places they don't belong will never think about until it is too late. They don't realize their friends are going to leave them high and dry or that there is no shame in staying you aren't comfortable. They may not realize how different the terrain actually is, because the great skiers do make it look easy. Whatever the case may be, they end up with a crappy surprise.
I was a figure skater from a young age, and started coaching at age 15. I have taught everyone from 2 year olds to 70 year olds, never-evers through competitors and some power skating to hockey players. Because of the "take lessons" mentality I had there and the fact that I know I am a very breakable adult, I didn't even consider getting in to skiing without taking lessons. I didn't want to add any external pressure to succeed, so my BF who has been skiing for 25+ years wasn't told I was going that day until after my lesson, and I greatly surprised myself in how well I did. I actually expected my figure skating experience to be a hindrance, as I was used to handling something 8 inches long and a quarter inch thick (oh the dirty jokes I can think of). I expected to be a complete spaz on skis, since they were just soooo different. Most of my class had been on skis before, so I expected to lag behind some. Much to my surprise, I didn't totally suck and the instructor actually pulled me out of the group towards the end to do a little more work at a faster speed with another instructor who's lesson ended earlier. As silly as it may sound, I think my complete lack of expectations helped me do better... I wasn't all trapped in my head. The whole being trapped in my head thing is pretty common for me. After that lesson, I took myself to the bunny hill and worked more than anything on stopping skills. A snowplow just didn't inspire confidence in me, and I worked until I figured out how to hockey stop on skis, on both sides (even if one side was shakier, it always was my weak side skating). Only after that did I go and leave the bunny slope to do a green run. I was much more worried about the stopping than the going.
Eventually, my BF came with and I took a lesson in the morning while he went and played. Little did I know, he was being sneaky and also watching me ski in my lesson. After I was done, he skied a couple greens with me and pushed me to get on a blue. I was pretty adamant that I did not belong there, but he was more adamant that I did. I told him that if I trusted him and ended up scared s**tless and couldn't handle it, he has to find another way home. I meant it, and he knew I did. He persisted, and I went. I made it down just fine, like he said I would, and had far more fun than I had on any of the green runs. I skied every blue that was open that day. The first time I skied a black diamond at Hunter was the same situation. I didn't want to go past blues, but knew in some way I was being "chicken". I was being fearful of something that I built up in my mind to be beyond what I thought I should be doing my second winter on skis. He never abandoned me, and stayed patient when I took much longer than he would to get down. He understands I am not going to go as fast as he is, and doesn't expect me to. After skiing the run very conservatively, I'd go back, hold back less and let myself enjoy it a bit more, then more the next time.
These instances of being pushed out of my comfort zone ended up being entirely in my favor, but I can completely see how trusting friends or a SO can get someone in a bad spot. I think most people want to believe we can trust our SO's, family, and friends, but that is just not always the case. They care about us, right? So how are they going to put us in a bad place? Sometimes it is innocent and they don't mean to get us in trouble, but other times I think showing off or a sink-or-swim mentality is involved and that is just dangerous. I don't need to see him zip down a double diamond to know he is way better than I am, nor does he need to be seen doing it. I'm not sure what separates the people who need that ego boost and validation from the ones who don't, but I am very happy to be with someone who doesn't need it. It doesn't seem to be just limited to the young or immature, although, IMO it is more common there. I have seen the behavior in people I know who are otherwise mature and successful people. Add in the other person's fear of being made fun of or whatever makes them go along with it, and you have a recipe for disaster.
