Flexibility and Perseverance
Have you ever gone out to photograph the sunrise, only to find out that it had turned cloudy overnight and there wasn't going to be much of a sunrise that morning? I have — more then once. The first time it happened to me I was faced with the decision of whether to go back to bed (it was 4:30 AM) or go out anyway and hope for a break in the clouds for the sun to poke through. In the end, everything worked out great, but it was touch and go right up until sunrise. Other times I've just ended up shooting other subjects when things didn't clear up. Still other times I have gone back to bed.
One thing that makes nature photography different from studio work is that you have very little actual control over your subject. You may go out intending to photograph one thing, but if that doesn't work out or if something else comes your way, you need to be ready for it.
On the other side of the coin, sometimes you need to be willing to persevere to get the photo you are after. If the wind is blowing and disturbing the surface of the lake, you have to be willing to wait for it to become calm to capture the reflection image you are after.
Learning when to be flexible and when to persevere can be a challenge. There are no right answers; only different choices. Let your experience be your guide and know that no matter how things turn out, it can be an opportunity to learn for next time.