Why does entropy always increase, simply?

Entropy is a measure of disorder or randomness. In simple terms, it always increases because there are far more ways for things to be disordered than ordered. Think of a shuffled deck of cards: there are billions of random orders, but only one perfect order. Systems naturally move toward the most probable state, which is maximum disorder. Energy spreads out, particles mix, and without outside energy, order tends to break down. So, the universe is always moving toward more chaos. This is the second law of thermodynamics, and it's why your room gets messy without you even trying!