Yeah, like others are saying, stretching and yoga are good. My mom is a yoga instructor, she actually (as an adult overtime) has grown about an inch! It also keeps you from shrinking, in a way, growing!
Before snapping back when someone says or does something you don't like, or asks you to do something you don't want to do - close your mouth, take a deep breath & say nothing for a few seconds, or longer. Give their ideas & thoughts a moment to sink in before saying or thinking "no way." It takes practice & patience to learn to control your emotions. Luckily, a little thought before speaking or reacting becomes a pretty good habit, quickly. Ask yourself if what they're saying or requesting is truly unreasonable? Are your beliefs & ideas the only viewpoint that matters? Usually not.