This explains a few things:
Researchers have repeatedly tied the [genetic] variant, known as DRD4-7R and carried by roughly 20% of all humans, to curiosity and restlessness. Dozens of human studies have found that 7R makes people more likely to take risks; explore new places, ideas, foods, relationships, drugs, or sexual opportunities; and generally embrace movement, change, and adventure. Studies in animals simulating 7R’s actions suggest it increases their taste for both movement and novelty. (Not coincidentally, it is also closely associated with ADHD.) — Restless Genes, National Geographic, Jan 2013, pg 44
I’ve always wondered why so many of the people I grew up don’t travel and are content to never leave the area in which they were born. The genetic difference is why it’s just not possible to explain to them why I did, why I climb mountains, why I’m restless, and why I thirst for adventure.