A leopard and its spots

It is my opinion that... the proverbial "leopard" can in fact change its spots. Someone told me that people cannot change because you are intrinsically who you are. A leopard cannot change its spots just like you cannot change the nature of who you are. If you are a gossip or a liar, then that's who you will always be. If you are too trusting you will forever be too trusting of people. I have to respectfully disagree with that viewpoint.
You live your life and you learn from your various experiences, or at least the hope is that you learn from your experiences. For example, if you tend to be a gossip, at some point, that will come back to bite you in the butt. Once that happens, one would hope that the next time you're inclined to spread news about someone, you'll recall the previous repercussions and stop yourself.
If you are someone who is very trusting, and you confide in those you consider your friends, but then you hear your business coming out of someone else's mouth, obviously the person you trusted cannot be trusted. Why confide in that person again?
I know that people are inherently who they are and their characters are pretty much set from the time they are very young, BUT, if you find that who you are isn't working out in your best interests, wouldn't it make sense to change some things about yourself?
When a baby touches the fire and gets burned, that baby stays away from the fire and won't touch it again, because the memory of being burned is there. Why should it be different for adults? True, some people never learn and continue making the same bad decisions over and over, but I don't believe that is true for everyone. Although it may be your nature to be one way, if you are motivated enough, you can make changes. I know that I have changed a lot in just the last few years, and some of those changes are in my character and who I believe I am as a person. I've had to learn several lessons the hard way, and so now instead of getting burned again, I proceed with caution or I walk around the fire. I'm not the same person I was ten years ago, or even two years ago. I've endured a lot and I've learned a lot about myself and people I choose to be around, so yes, I have changed my spots so to speak. It is definitely my opinion that while those spots may not change altogether, they may change definition or simply fade away.