Scientists believe we hardwire our brains with less than stellar activities, making those habits — like smoking, drinking, overeating, etc. — difficult, but not impossible, to break.

Here's more from MSNBC.com:

Uh-oh, the new year's just begun and already you're finding it hard to keep those resolutions to junk the junk food, get off the couch or kick smoking. There's a biological reason a lot of our bad habits are so hard to break — they get wired into our brains.

That's not an excuse to give up. Understanding how unhealthy behaviors become ingrained has scientists learning some tricks that may help good habits replace the bad.

"Why are bad habits stronger? You're fighting against the power of an immediate reward," says Dr. Nora Volkow, director of the National Institute on Drug Abuse and an authority on the brain's pleasure pathway.

It's the fudge vs. broccoli choice: Chocolate's yum factor tends to beat out the knowledge that sticking with veggies brings an eventual reward of lost pounds.

"We all as creatures are hard-wired that way, to give greater value to an immediate reward as opposed to something that's delayed," Volkow says.

Just how that bit of happiness turns into a habit involves a pleasure-sensing chemical named dopamine. It conditions the brain to want that reward again and again — reinforcing the connection each time — especially when it gets the right cue from your environment.

Read the rest of this article, by Lauran Neergaard, here.

But, there's still hope. This lady says she's figured out how to re-train your brain:

Rhiannon "Rhi" Bowman is an independent journalist who contributes snarky commentary on Creative Loafing's CLog blog four days a week in addition to writing for several other local media organizations. To learn more, click the links or follow Rhi on Twitter.