the contradiction

I had once said that one's action is his/her choice. It is.
But there is something in nature known as 'devil'. The devil will look out for that one moment in which one is low on life and then will attack. By devil I don't mean a fixed person, a person might act as a devil just for one person or it just might be a negative phase of their life or it might as well be a sad simple case of bad upbringing. So the question one is left with is how to dodge the devil.
This question was injected recently into my brain a few days back when, after a long while(3 years almost), I got into a MKOB (my kind of brawl). There were 0.001 percent odds that what happened could ever happen. But it happened.
So I hereby alter my saying
One's action is his/her choice ONLY when nature decides to protect them , when one has unwavering faith and when one derives strength from only happiness and nothing else.
And if this be a reality then nothing can affect one's actions. nothing!