I'm pretty sure Pollock thought he had ruined his canvas when he accidentally let some drippings from his large brush fall into the clean-neat surface.
At the time he didn't realize how influential, innovative and avant-garde his little accident would be.
Truth is, Pollock had already ventured into this sort of expressive spontaneity in drippings and splatters.
But it wasn't 'til he went large scale and bought many gallons of house paint that he became serious and really engaged into this new experiment. Many of his colleagues, including Siqueiros and Lee Krasner (his wife) were great influences on his work.
Thanks to his work, the term action painting was brilliantly engraved into his lifetime. Action painting is a painting made with splatters, pours, and harsh brush strokes. Many find this a very therapeutic type of painting and often seems like much is also infused in the character of the work: passion and sometimes anger and confusion.
What's most interesting about this type of painting is being able to see it both at a distance and up close.
Most of the pieces are quite large anad carry a great deal of detail that can be appreciated: drips joining, the three dimensionality conveyed by the layering of paints and the rich texture of the splatters.
Sometimes one cannot feel but a bit saddened when knowing Mr. Pollock had a troublesome life dealing with alcoholism and anger. It's unavoidable to sometimes see that in his work: some paintings seem a bit more confusing and gray, others a lot more as a release of store energy and thought.
His work continues to be influential and avant-gard even now. And surely an art form to remember and a necessary chapter in Art History books.
How to choose a career that allows such creative freedom?
Perhaps you want to consider a Fine Arts Degree in Painting.
I highly recommend it.