Not everyone is aware that they need it, but yeah, everyone needs it.
Obviously we need to, because if we don’t, there are consequences. God does not need anything (or ‘God does not need anything’) but he does have desires. He desires his children to love him back. He does have requirements for us however, not that our fulfillment of them will earn us anything.
There are two kinds of grace. So you are correct regarding the first kind, common grace – if we don’t recognize it, we don’t know that we have it. We cannot not have it and no, it certainly does not need validation. But knowing that we have it, we can be thankful. (God doesn’t owe us anything – tragedies are tragic and I weep over them, but that’s life, unfortunately to sound callous and blasé.)
That we’re still here is evidence of that there is such a thing. 
The alternative is maybe vaporization?
If it were not for God’s patience and love through the work of Christ, wanting to adopt more into his family, the earth would have been a cinder long ago. God doesn’t owe us anything.
Because of the LORD’s great love we are not consumed, for his compassions never fail.
Lamentations 3:22
ETA:
They are new every morning; great is your faithfulness.
Lamentations 3:23
Hence the famous hymn.