Vertical thinking reminded me of biases. I think vertical thinking feels natural because our brains like to use patterns and logic to make things easier. We naturally look for shortcuts to save time and effort (biases like the confirmation, anchoring, etc). Also since vertical thinking can be learned, just as biases.
The thing is biases can be efficient/fast but incorrect similarly to how vertical thinking can make us miss out on creative solutions and new ideas because we get stuck in the same way of thinking.
Both types of thinking are good and we get different things out of them. We can rely on the logical methods of vertical thinking and also use the flexible approaches of lateral thinking to find new solutions.