Show me the light

Even when you can't see the light at the end of the tunnel you know it's there, but if you can't actually see it at this point in the tunnel is it worth plowing on. Because it is there, you know it is, it's just the possibility of turning around or maybe escaping through a sewage tunnel might be an easier route. Especially if said tunnel has become increasingly frustrating and potentially not worth the bother - for this metaphor, lets just say there are a lot of other cars going through the same tunnel in rush hour.

The thing is, is there are other options open and even though the ultimate goal was to reach the end of the tunnel it's not as if there's any particular reward for reaching it (maybe the opportunity to earn a little more money) but when there are other things to see, people to do etc etc. it's like... really? The shortcut is there, it is an option.