What problem do parents have with their kids playing video games

If boundaries and time frames are not set, nowadays, boys especially, think that is the only thing they have to do and want to do. I give my son a 1/2 hour a day, 1 hour if its raining, with any of his electronic, including the household computer. This is as long as he has done his chores and been behaving properly. If not, no electronics. They seem to get in a zone and I believe they become addicted to it, on some level. I also have seen for myself and heard from other parents that when it does come to other activities, if they dont get instant gratification, like a reward in a video game, they get annoyed with themselves and when they lose at something or do poorly at something, they think they are a failure. I told my son early on that electronics games are a fantasy world sometimes created from real life situations that most likely he will never be involved in other than on his "gameboy" lets say, so use it as a form of entertainment not a guideline to your daily living.