Awww :(( try & tell them how you feel, so they can include you more!!!:)
Self defense is perfect example. You have a right to kill someone in order to prevent them from killing you if the danger to your life is immediate and inescapable.
People started learning how to use technology and motors, battery powered things... so back when the pony express was a thing people would use to get around, we didn't know what cars where so people started building structures using aerodynamics so use cars, trucks, and trains now a days