I think we live in a "do what you want, just don't get caught" kind of society, and that breeds secretiveness. As a teenager, most of my friends lived under the constant threat of being grounded for breaking the rules. So as a result, they learned to do what they were going to do, but to lie and sneak around while doing it. My mom took a more "natural consequences" approach: go ahead and make boneheaded mistakes, but don't expect anyone else to fix them. It taught me that it's ok to fall flat on my face, and it taught me how to pick myself up afterwards.
I feel terrible for my step-daughter, whose mom has raised her to lie and manipulate, by lying and manipulating her. The mom was the child of alcoholics so this is how she was raised herself. We try to do what we can by being open and honest with her, and by rewarding her for being honest, but we're losing the battle. She goes through friends like they're going out of style, and my husband is pretty sure it's because they see through her bullshit and send her packing.
Most grown-ups lie and cheat because somewhere along the way, someone [unintentionally] taught them that it's the only way to do what makes you happy without bringing the roof crashing down on your head. Thank you Mom, for letting me be me!
Labels are sticky and I hate the glue they leave behind.