I believe without a shadow of a doubt that Karma is real.

According to Webster's Dictionary, one definition of Karma is:  The doctrine of fate as the inflexible result of cause and effect; the theory of inevitable consequence.

In simpler terms:

If you do good then good things will happen to you.
If you do bad then bad things will happen to you.

Let's take a look at how all of this works in real life. 

If you do good then good things will happen to you.  So with this knowledge in hand you start doing good deeds and become a sparkling example of a positive well meaning person.  Heck you turn into a regular boyscout.  You let other people take the close in parking spot at the mall, you hold the door open at the supermarket for the senior citizen (you say senior citizen instead of geezer), you make it a point to share credit for everything you do with other people (no matter how small their contribution), and you are a top notch positive person.

You have done your part, now it is time for Karma to do it's part.  But wait!  Karma does not work on your schedule.  That's right, actually Karma does not work on any schedule. 

Karma is a doctrine of opportunity.  What does that mean?  It means that Karma will show itself when the consequences that it brings will have the largest, and in this case, most positive impact. 

So how does that affect the well meaning, do gooder, boy scout, positive, helpful person that you have become?

It affects you like this:  You will get the benefits of Karma, but you can't expect immediate gratification.  You will have to continue to do good while Karma waits for the perfect opportunity to reward you for past actions.

For the most part you won't even realize when "Good Karma" has visited you.  The good deed or action that you had been a part of could have happened months or even years ago.  The "Good Karma" could show up years later when that perfect job opportunity presents itself and despite 20 other well qualified applicants viaing for the same job, you end up getting it.  You wouldn't even realize that it was "Good Karma" at work.  And you certainly wouldn't connect the dots between what happened a year ago and what happens today.  But that is how Karma works.  You must operate on faith.

If you do bad then bad things will happen to you.  That's right, do not ever think for a single moment that you, me, or anybody else is going to get away with doing bad, negative, or harmful things to other people.  If you do make that mistake then you are in for a very big surprise. 

The one thing that you can anticipate with certainty is the "Bad Karma" will present itself at the worst possible moment.

Bad Karma will not let any bad, hurtful, or negative action go unpunished.  Like "Good Karma" the negative action could have taken place a year ago or ten years ago but rest assured "Bad Karma" is just waiting for the perfect opportunity to visit you.