Born this way
In a sense, Lady Gaga was right. We might not have all our flavors baked in at first, but as we grow in our first few years, we certainly pick up a lot things that shape how we see, feel, and think. If raised in a home filled with tension and conflict, you learn to be on edge - living in fear and in defense mode all the time. If that is extended into school, work, or other environments, you just live that way. Vice versa, if you grow up in a peaceful, reassuring environment with teachers, friends, and all the people you're around normally being encouraging, etc, you'll have more confidence and less defensiveness. Or to use a different dynamic, you can grow up dreading work and prefer relaxing and doing less physically demanding things. Or vice versa - you might dislike sitting still and not being busy. You can make a long list of different kinds of variables a person can experience growing up that make them feel "born this way" as their life unfolds and they develop ...