For obvious survival reasons we evolved to have sensory/cognitive access to our own activity, self-monitoring, and self-modeling ourselves.
The self-modeling, is in such a tight loop, it melds "ourselves" and our model of ourselves, our thinking and choices, and experience of our thinking and choices, into one component.
Like you can't analyze half a wheel of a bicycle and be talking about the same thing.
This awareness, increased modeling, control, feedback loop has tightened up over many stages. Just a few:
1. The body-sense loop
2. The internalized-environment-model loop
3. The body-internal-function loop
4. The body-internal-model loop
5. The emotional-cognitive loop
6. And finally, the tightest loop of all, our high-level cognitive activity, experienced as feedback directly, our self-model, and our self-direction, all merged into one thing.
We literally spend almost all day, every day, thinking about ourselves, in terms of our inner self.
That is consciousness. Rich self awareness, a merger of self-model and self-direction, and all in service of understanding and managing ourselves. Hw we can leverage our greatest tool, our self-directable mind, its habits, views, and behavior.
This wasn't an accident. A happy side-effect of our brains. It is a biologically evolved focusing of our highest-level behavior, with tight feedback, constant self-modeling and continuous focus on our inner status as motivation and most privileged object of our control. It has been ruthlessly optimized for, for a very long time.