I know what you mean - I used to worry about this before I became a Mommy.
I have to tell you though that from my experience, when its your own children, it is almost a non-issue. You love them so much that you kind of forget about all that. Sure, sometimes are difficult like when they get sick or misbehave, but they are only temporary. As for discipline, if you are consistent and follow through every time with consequences, you will raise happy, obedient, pleasant children. Children who are not disciplined properly are a mess and a pain to be around.
If you raise your children without TV, music constantly on, or too many toys - they grow to be independent, imaginative and creative children who don't always whine "I'm bored". Children who are given too much become overstimulated and dependent on others for entertainment.
Now, as for other people's children - ugh. I have trouble with this. A friend of mine with 3 children wants to get together all the time - I have to turn her down often. Not only do I get cranky and overwhelmed - but so does my daughter! LOL I guess she is a chip off of the old block. I allow limited playdates for social interaction but I monitor what goes on very carefully and keep the TV OFF. It keeps the mood more calm, I've found.