Short circuit - bypass or impede

Cognitive dissonance - conflict from holding two conflicting beliefs simultaneously

So it's a way to either prevent or stop mental frustration due to conflict between two beliefs.

For example, X needs to be fixed, but fixing it will take too much effort. "It is what it is," so we'll just accept it being broken as a given and work around it. If you didn't short-circuit the line of thinking, you'd spend a ton of time on something that can't reasonably be fixed.