Common grace is a term for the grace which God bestows on all mankind. This is different then a saving grace.
Since all men have sinned we all deserve the wrath of God. Common grace is the good which God brings on men in this current life.
All people have experienced the blessing of God to some degree. He does not simply bless his children.
God pours out the rain on the just and the unjust. The reality is God has a great patience.
A lot of people think that God is out to get them. If God was out to get them then they would not be standing - he is too strong.
The reality is that God sits in heaven offering grace and hoping that we will receive it.