Does good intent exonerate you from negative consequences?

The aphorism goes: the road to hell is paved with good intentions. I wonder whether it is actions and results that count, or, if it is intent that counts. What do you think? If a person meant well, does that let them off the hook? Do you think that if you have good intentions, that that defines reality? I.e. it is not possible to have negative consequences if your intent was a good one? If it does not let someone off the hook, does it ameliorate their culpability?