Why do people sometimes make irrational decisions against their best interest?

People sometimes choose things that don’t seem smart because their brain is playing a tricky game.

Imagine you have two cookies, one is big and soft, and the other is small and hard. You know the big cookie tastes better, but the small one is right in front of you. Sometimes your brain says, “Let’s take the small one now!” even if it means missing out on something better later. That's like when you pick a toy you already have instead of waiting for a bigger one.

Your brain works fast, but it doesn’t always think about what happens next. It’s more like a kid who sees candy and grabs it right away, even if they know eating too much will make them sad later.

Sometimes, your brain gets confused by noise or excitement. For example, you might see a toy that’s really cool, but it costs a lot of money. Your brain might say, “I want it now!” instead of thinking about whether you’ll have enough money for ice cream after that.

So, even though you know what’s best, your brain can sometimes trick you into making choices that feel good in the moment, but not so great later on.