I run into this one on a daily basis: "We need a brand for our company, let's create a logo." And their branded, right? Wrong. A logo is a visual representation of a brand. It is an excellent tool for communicating what a brand stands for, but it is not the core of the brand.
I like to think of it like a wardrobe. You can tell the world an awful lot about a person by the clothes they choose to wear: their socioeconomic status, their interests, who they aspire to, how much time and energy they put into their beauty regimen. These are all very descriptive things, but do nothing to describe a person's story, their background, their attitude, their perspective, and their values. All crucial components to being human. Like people, great brands have deeper layers that make up the foundation of who they are, the commitments they are making to their customers and their ability to follow through.
ps this is an incredibly complex process, which is why it is often applied poorly or misunderstood.