Self deception and cognitive dissonance are actually distinct from each other.

As you say self deception is easy to fall into. I have on at least one occasion I can remember thought doing something was stupid, and then realized I had done the same thing.

My face still burns from blushing when I think about it.

I don't know which that scenario would fall under, but I know it wasn't pleasant, and it always makes me pause and try to see things from outside my own perspective.