the Road to hell is paved with good intentions

I’ve heard this phrase many many times but Never understood it completely.. what exactly does it mean?

There are some people…who have good intentions but somehow, they end up saying the wrong thing, or do something that may be unintentionally hurtful to someone else.

How long can one live and act just on good intentions? If a person has tried thier best and someone else still continues to get hurt or upset at their antics or words…what is the solution? Should they just drop the person? try harder? stp trying?