Yeah, when I bought two new tires for my car, I told the shop to put the new ones on the front cuz it was a front wheel drive car, and it made sense to have the new tires on the front where the power and steering happen.

But the guy at the tire shop said that it's actually safer to put the best tires on the back. The idea is that it's the traction of the rear tires that keep the car pointed forward. If the rear tires slip on the road then the car can spin out, and you lose all control over the car. As long as the car is pointed forward, you still stand a pretty good chance of regaining traction and control by just taking your foot off the gas and letting the car slow down. But, as soon as the car starts to spin out, then you have much less chance because you instinctively turned the steering wheel as the car started to spin out, and now you don't even know what direction the front wheels are pointing, and at highway speeds you might not figure that out in time to avoid the ditch or a head-on collision if and when you regain traction.

At least, that's the way they explained it to me, and it made some kinda horse sense.