The choice is always yours

Yesterday I was returning home after watching a movie and decided to take the metro. As I reached the platform the metro train was leaving and I stood there seeing it leave without me. The next metro would come in another 4 minutes. Recently queues have been started to form at the metro station for boarding the metro - a nice initiative taken by the metro body I must say. And here I was now in the front of the queue (now that's an achievement in itself isn't it?). And since I had nothing to do for the next 4 minutes I got lost in my thoughts wondering whether I should be happy or sad on my current situation. I could be sad that I missed the last metro by a whisker. Or I could be happy that I will be the first person to board the next metro. What do I do?
And it brought me to think that life is just like that. In every opportunity you have the option of choosing whether to be happy or sad and the choice is entirely up to you. There's a line between being happy and being sad. And you cand ecide on which side of the line to stand. You can always regret on a lot of things that lead to the scenario; and if that is not enough you can always think of things that might happen if something goes wrong. On the contrary you could always think of what else could have wrong which didn't and now you are in a better position; and also you maythink of the good things that are going to happen from the position you are currently in.
The choice is always yours. People do things but not always it turns out the way they want it to and they have to start again. Some people say they made a mistake while others prefer to call it experience. What you would do is entirely your choice.