Rain rain rain....and complaints!

Here comes the rain and when it comes people start commenting like "Oh God its raining again," or "Oh no! I will get wet again," etc. You can think of adding up the profanities in it as well..I just didn't want to elaborate the statements with them. So before it rains and is hot/humid, people are complaining about the sun and the heat. The point is most people (including me) never stop complaining. But what is the problem with human psychology? Why do we only see the "bad" side of the coin and not the bright one? Are we conditioned to be this way or the life patterns these days have made us so?