Well, practice saying it... More importantly, what do you see in yourself that you wish people saw in you? Maybe a better way of stating it; what do you HOPE that people see in you when they get to know you? And not just what you like, who you are, but WHY!
Ex: (Not me!) "I'd say that I am open to new experiences, but as much as I enjoy learning new things, I really like perfecting the things I already do and finding new ways to do them better. I compete with myself more than with other people and I like outdoor sports like running where I train and then compete and socialize with others. I love cooking because I like to see other people enjoy what I make, even though they don't always!"
So what was said there? That you are self motivated, that you are driven and competitive, that you are steady and exacting with tasks, that you enjoy making other people happy, enjoy socializing, the outdoors, and learning new skills.
Is that answer going to get you in? Maybe, depends on what they are looking for. Is it a CORRECT answer? If that is you. Is it a WELL FORMED answer? Yes, it gives them an idea of how you will cope with school.
You could have said the opposite:
Ex: "I'd say that I live for new experiences, but as much as I like new challenges; I always try and make myself improve the things that are already a part of my life so that I am always improving. I love team competition and forming a good group dynamic. It brings out the best in every team member, and it builds problem-solving skills and leadership. When I'm not in a group environment though, I really love my alone time where I can veg or reflect on recent events. Sometimes I like to write, even though I don't share it, because I can read my work later in life and remember where I was then as a person, and compare it to where I am now."
What did that say? That you are a dynamic member of a group and add value to a team. You see life as a "team" event and seek to lift those around you and accept the hand of those with more experience. You thrive on expanding your horizons, but you don't simply replace one infatuation with another. When you are alone, you are still content and confident, and introspective. You see the big picture and find the journey as important as the goal.
Again... you can see a medical school wanting either of those people. It all depends on the school. But the same things are there: how you measure yourself, how you interact with people, what you do for fun, how you view life.
Nutshell: it ain't what you say, it is how you say it. Be honest, but put your best foot forward.