I live in a very low crime area, yet even in my sleepy neighborhood (semi rural), we had a break-in a couple years before buying our house. It turned out to be a couple of teenagers that wanted some quick cash (probably for drugs). That was the only break-in for years, and there hasn't been one for the several years I've lived in my house, so you never know when someone will try to steal something.

That being said, a lock has to be just good enough to deter theft. In my area, that's means a simple door lock for houses and a U-lock for bicycles. In other areas, you need far more security. But to goal isn't to keep out a determined attacker, but to make it more worthwhile for the thief to move on to the next house/car/bike than to try to get past your lock.