I have learned many lessons while pursuing photography as a hobby.
1. It doesn't matter if you always get a good picture
This might sound contrary to the whole pursuit of photography, but it's really true. While you may not always get a nice photograph, you still gain wonderful mental pictures which are just as satisfying, and in the long run really do last longer. In addition, for me photography is as much about the process as it is the result. If I were to go for a normal walk, without a camera, I would probably tire easily. But I can walk for miles with a camera without thinking about how far I have come. Walking with an eye focused on recognizing the art around me is just as enjoyable as the pictures I'm able to get.
2. You might not get the picture that you want, but you might get something better.
I have often found that when I focus all my attention on one scene, I miss the little things around me. Today I was looking at the water as I walked around the reservoir. Something above me drew my attention, and I saw this hummingbird. I noticed that there was a swarm of flies around him, and he was eating to his heart's content. While the reservoir might have made a nice picture, this one of the hummingbird is much more intriguing to me.
3. Sometimes you are given a gift.
Sometimes when I am focused on one thing when taking pictures, suddenly I see something that I think can best be described as a gift. For example, you spend your efforts trying to take a picture of something, only to look down and see that a butterfly has landed right next to you. You take a picture of that, and in the end find it may well be one of the best pics of the day. But it isn't until you try to recreate that setting by following a butterfly, waiting for it to land, that you realize what a gift you were given the first time. The media coined the phrase, "Kodak Moment", but I like to think of them as "Gifts". Case in point: I have been "stalking" this Blue Heron for weeks now. Maybe he is getting used to me, but he let me get very close today and I got the "gift" shot that I have been wanting. :)