Occam's Razor is an idea that the simplest answer is likely the correct one. It's called "razor" because it "shaves off" unlikely explanations.
Your brain does this automatically. Allow me to demonstrate: Close your eyes and imagine you are looking out a window. Outside, there’s snow everywhere. It’s still snowing. What time of year is it, based on that one bit of information? Your likely thinking that it’s winter. It snows in winter. It’s the most logical answer. It’s the simplest answer.
Let’s do another thought experiment: Your friend Bill stops by. His nose is red. He’s sneezing a lot. He’s got a handful of tissues and he’s warning you to stay back.
What’s wrong with Bill? Well, obviously he’s not your friend at all, since he’s trying to get you sick. But you assume, based on this alone, that he’s got a cold. Perhaps the flu. Unless you are a medical professional; then you might have a different perspective on Bill’s ailment. Still, the average person isn’t going to go all in and assume Bill’s got cancer. He’s got a cold. It’s the simplest answer.
Obviously, there are sometimes things that don’t fall into this line of thinking. I know you’re out there, you naysayer, ready to attack me with some anecdotal story about how something happened to you or a friend or your crotchety old cat lady aunt. I can hear you now. “It wasn’t simple, it was this round about thing and aliens, UFOs, and even a dog were involved.”
Sure. Outliers happen. Sometimes crazy stuff throws off our general ideas of how the world works. But most of the time, the simplest answer is likely the correct one.