I am absolutely terrible at delaying gratification (ADHD side effect), but I have been very pleased to note that my 3 year-old does it routinely. When given a treat, he'll often have a nibble, and store the rest away for later. I suspect it's a fairly natural stage that kids go through, but it requires encouragement to become established for life. Similarly, kids will go through stages where they exhibit pretty negative traits, and parents should respond by discouraging those behaviors (don't hit your sister!).
For people not connected to the technological world, heavy use of electronic devices might appear to be some kind of addiction. I feel sorry for those people, because when the singularity comes, they will be unfortunate casualties. Games are merely an alternate reality in which people can live quite happily as long as it's sustainable. Once we're connected to the 'net through myriads of implanted devices to have those devices disabled would be devastating.
My sister opened a computer store in Hawaii. She sells C shells down by the seashore.