It is a fantasy shared by many Americans: dropping cable television and its fat monthly bills and turning instead to the wide-open frontier of Internet video.

Some are finding that the reality is not that simple.

Just ask Bill Mitchell, a 40-year-old engineer in Winston-Salem, N.C. He canceled his Time Warner cable service and connected his flat-panel television to the Internet to watch sitcoms and his other favorite shows, using products from Apple and Boxee.

His experiment lasted 12 months. Recently, grudgingly, he returned to his $130-a-month cable subscription, partly because his family wanted programming that was not available online.

“The problem is, we’re hooked on shows on HBO and Showtime, like ‘True Blood’ and ‘Dexter,’ ” he said, adding that he wishes he could buy only the shows he wants instead of big bundles of channels he doesn’t. “It’s so frustrating.”