Originally Answered: why are there so many commercials on T.V. i am so tired of long commercials.?
It's interesting, because if you think about it, TV actually exists more for advertisement than for entertainment.
It's not necessarily just that the commercials pay for the shows, so much as the shows exist to sell commercials...all networks could do as HBO, Showtime, and even Disney 15 years ago, and have you pay for the channel and get rid of commercials. These channels typically have better programming even.
Ultimately, the only reason networks want quality programming is so that more people will watch. If more people watch, they can sell their advertising slots for more money. The networks are only concerned about what you like indirectly. The first questions is: "how can we sell these advertising slots?".
Think of the Super Bowl, and how a lot of people watch more for the commercials (though most are there for the game). It's become a cultural thing to watch the championship game of the most popular sport in the country and see what interesting commercials will be broadcast on a given year. The networks know this, and the one that gets the rights to the game banks off of it.
Furthermore, think about when respected awards shows are on. Do any of the network channels run new episodes of their shows on the night of the Oscars? the Emmy's? No, because fewer people are going to watch. The advertisers know this, and so they're not going to pay as much for a slot of a new episode of Lost if it's going up against the Oscars.
It's all about advertising...we live in a consumer culture (and very much so).
If you talk to someone who studies Modern Culture and Media, you'll get some very interesting perspectives on the televisual experience. Ultimately however, the culture of TV, like the economy of TV, is very much involved with commercials. When watching a movie in a theater, you don't really get up unless you have to (bathroom) or really want to before the movie gets to its pivotal moments (popcorn). It's different with television. You get up during commercials, you might talk on the phone with your friends, you might do your homework, go to the restroom at your leisure, make dinner and do your chores, etc. It's a different experience, and commercials, the typical setting of television viewing, etc. all have a lot to do with it.
But yeah...DVR's aren't the cheapest way to avoid commercials, but are the best way to go. DVD burners can be complicated/frustrating, and are not as reliable. VCRs are outdated of course, but are definitely the cheapest way to go (if they still even sell VHS tapes).
In response to Connie B - it makes sense that different programs seem to have commercials at the same time. Different shows have different strategies, but there are people who are paid to study the televisual habits of consumers/audiences/etc. After compiling data, they determine what they have surmised to be the best placement/spacing of commercials and they run with it. That several networks adopt similar policies (that have been shown to be effective) is not surprising.