I watched Lassie as a kid, but I found it really scary. All kidding aside, that Timmy got into some serious peril. I remember at one point being afraid to go in the wood when visiting my grandparents in the American South, because as Lassie taught me, the woods were full of mountain lions ready to pounce, and I had no loyal collie dog to save my wimpy butt.
Really, that show also ruins dogs for children. No real dog is ever as awesome as Lassie. I loved my childhood dog (an Australian Shepard named Maggie) dearly, but we never got to go on adventures like Timmy and Lassie. One of my many disappointments.