A tunnel is just a road that got through the mountain instead of around it.

Going through is not a failure to find the easy route. It is a different solution with a different cost, and often the shorter one in the end, though every metre of it is harder than driving around. The dark stretch in the middle is not a sign of a wrong turn. It is what the method involves.

If you are in something long and unlit right now, check that you chose it rather than fell into it. If you did choose it, stop reevaluating the decision every morning. Note the distance covered and let the missing view be an ordinary feature of tunnels.