Child whats wrong?

Have you ever noticed that when we were little it was okay to talk. If we fell down and scrapped our knee, or if some other kid pushes you at the park it was okay to talk. Talk to your friends and family. But as we grow up we slowly clam up. Not due to the theory of "no body cares" but due to the central belief that we feel more and express more. Even the smallest mouse can leave the biggest footprint in the sand.
What I'm trying to get at is that as adults when ever we feel down or have something on our mind we shut our shells and clam up trying to hide any weakness or flaw within ourselves. Yet when someone asks us and we say no "nothing at all" we scream the total opposite inside our minds.
Not to sound totally cliché or anything but WHAT IF we changed that, what if we decided to open up and jump into the realm of possibilities,instead of just dipping our toes in. Then perhaps our lives in general,our emotions that are bottled up, wouldn't be as stuffy,stiff, and we as people would be able to move freely like we did when we were little.