According to Osho, unexpected joy feels like a miracle only because you had forgotten your own nature. Nothing impossible happens: when the mind becomes still and obstructions drop, your innate fullness reveals itself. The 'bag' was already full; you simply hadn’t looked within. Emptiness of thought invites the Divine from all directions, and what always was is suddenly recognized as joy.
When joy surprises you, it’s just you finally noticing the treasure already in your pocket after the inner noise stops.