What Makes a Planet ‘Habitable’ or ‘Not Habitable’?

A planet is habitable if it can support life as we know it, like Earth. To be just right, a planet needs to be in the ‘Goldilocks Zone’, where it's not too hot (like Venus) or too cold (like Mars). Imagine it's like finding the perfect spot to sit on a sunny day: not under the blazing sun, not in the shade, but just right. If there's water, liquid water, and maybe some air, that planet could have life, just like us.