You Dont Have a Choice When It Hits You In the Face....As half a science major, I can't help but apply certain laws of the universe to the facts of life. Every action has an equal and opposite reaction.
Everything I have done has come back to me in turn. I have done good things with good intentions, and good things with bad intentions. That is my favorite part of karma: I subscribe to the common belief that you can't collect good deeds like extra lives in a video game and hope to sit back and be set for life.
It's all about the intention. When I got my boss fired from her job, and then took it, I knew I deserved it, but I perhaps didn't have to go so far to help her out of her comfortable seat in my office. It started out okay, but the job went on to destroy me.
That's one of the bigger examples, but I think all of the ups and downs in our days, weeks and year are just the cosmic waves ebbing and flowing in the tide of our lives. :)
Time to learn to surf....