When a believer says "God has been great," they are sharing a personal testimony of how they have experienced God's power and love. It shifts focus from personal merit to God's grace and faithfulness.

Overcoming adversity: A Christian might recall going through a trial and testify that God's presence, wisdom, or strength helped them through it.

Unexpected blessings: It can be an expression of thanks for unexpected good things, like a new job, a repaired relationship, or provision in a time of need.