Can one be close to God but not acknowledge it as such (for example, an atheist humanist who works to reduce suffering and improve the well-being of all) and, vv., can one think they are in heaven, but really they are far from God?
In my personal opinion, the whole purpose of this creation and temple of God, that is, the human being, was made to strive towards advancement and perfection through the virtues and attributes of God...
So, for me, even an atheist progresses spiritually through eir practice of virtues, because they are in themselves divine emanations from God's Essence and Being. In both Sufi Islam and the Baha'i Faith, the practice and development of virtues is in a sense, recognising God's presence in life.
After all, the Afterlife is eternal progression towards God in the spiritual worlds. Heaven and Hell are mere states of the soul's existence in its relation to eir distance from God's Presence.