There are of course exceptions. Famously, Palahniuk has said the Fight Club film captured his intent better than his novel did. I also think film of The English Patient, which covers only a tiny section of what I consider a forgettable novel, is quite good, but even if you disagree I think almost anyone would say the film is better. And of course plenty of films aren't novel adaptations.

Regardless, if you're looking for a "story that could change my life" you're likely to get much more from the text than the adaptation. The strengths and weaknesses of the two media are just too different.