What food/fitness/health "hack" has made a big difference for you?

I have started cutting up vegetables I buy at the grocery store as soon as I get them home, before putting in the refrigerator. I am far more likely to eat them when they are ready to snack on. Before, I would buy vegetables, let them sit in the fridge all week, and then throw them away since they'd rot before I could motivate myself to eat them.