I, personally, tell the difference by paying attention to and observing reality without making any judgments. Then, I compare that with my expectations based on my judgments. If there is a difference, then I am thinking I am interacting instead of interacting.

Over time, I stop making judgments. And in essence, I stop thinking about interacting with the world, and just interact, and see what happens.

I think it'd be useful to hear an example of "observing reality without making judgements" and "observing reality with making judgements". I'm having trouble figuring out what you believe the difference to be.