What Is The One Move You Learnt That Changed How You Play?

What is the one move or two you learnt that changed your gameplay in a positive way?

For me it was Steve's DF+1. It's a mid uppercut poke he does as well as crouch jab. I know pokes have been around but these are new to me (I'm a low level player). I use to get rushed by these aggressive players but ever since I started these pokes, I immediately break their aggressive play and end up flipping the aggression. Now they're not as aggressive anymore and it brought a lot more confidence within me.