Every time I start my computer it shows a picture of me holding two of my ice axes in front of K2. K2 is a scary looking mountain. My favorite mountain is Longs Peak in Colorado. It's over 14,000 feet and there is no really easy way to get up it and there are dozens of very hard ways to try and get up it. Also, it is a pretty stable place to be, at least in the summer. There are no crevasses or hanging glaciers.
Within the whole mountaineering/climbing realm there is a lot of fear. People who say they are not afraid of heights are lying or they really are crazy. Everyone is a little afraid. It's that fear that keeps people safe. It's that fear that gives us an adrenaline rush and keeps us coming back. A lot of people are addicted to this sport because of the fear.
However, everyone has a limit. Now for many people that limit is not yet realized and/or beyond the limit of everyone else in the world in his or her particular endeavor. Most people know they have crossed the limit when it becomes more scary than fun. That person does not enjoy the experience at all and can even be paralyzed by fear.
The saying is, "it doesn't have to be fun to be fun." Many of the best memories are made when some amount of suffering is happening. Many of my favorite days in the mountains are the days when I spent a lot of time afraid, cold, wet, hungry, tired, and wondering if I could actually finish what I set out to do.
In the outdoors I listen to my gut instinct. Many times I have turned around for the reason of me just not feeling comfortable with what I would have to do next. It is the point when the next step is scary and the perceived risk is higher than the potential reward. Fear is a nice thing to have in small amounts every now and then but there is a limit. There is a limit where life is more scary than fun. Turn around my friend and pick a new route.