Yeah exactly people do the same thing. There's good evidence that for the most part, our actions are driven by our "non-sentient" mind, and our sentient brain just decides justifications to explain a cohesive story as it goes along after it happens.

"Why did you do that?" -> attempt to make up an answer that will be believable both to self-identity and to the listener.

So what's the point of the executive mind if the hindbrain is doing all the walking and talking?

The primary benefit of this story-making is that it allows formulating predictions and discarding the least probable. When a believable prediction kicks in, the predictive brain incentivizes the hindbrain with a partial taste of any reward or pain, with promises of more should the path transpire.

Disclaimer: not a neuroscientist, just a lifelong enthusiast of the subject.

This is very believable. Post-rationalization just makes sense. Even if you come up with a shitty reason, at least you have _a_ reason for doing something.

Your comment is an example of itself.

Situations, where you don't make cohesive story, but stop and think "What the hell I'm doing?", aren't uncommon either.