The main character in a story is the protagonist. As readers we share the most empathy with this character. He/she is the one fighting for a cause in the story or movie.
The antagonist, on the other hand, is the protagonist's adversary. They are almost competing against one another. Usually they have some sort of conflict between each other.
When we think of good short storys, we know they include internal or external conflict. A great way for authors to get reader's attention is to show characters having conflicts. It makes it more interesting, because usually people can relate.
(MY LITTLE PONY) IS THE BEST SHOW EVER
The main character in a story is also called the protagonist. The protagonist is the person that the story is usually written about. He or she has a problem that needs to be solved or resolved and the author develops the plot around this character.
As readers we may or may not rally around the protagonist. This all depends upon how the author writes this particular character and how attached we become to this character. We may find ourselves cheering for the antagonist who is usually the one working against the protagonist keeping him or her from reaching their goals.
However, most readers want the protagonist, or main character to be successful and therefore in many books they usually are.