For my generation, at least, a great portion of the “knowledge” that people have about the USA comes from TV. Holidays such as Halloween and Thanksgiving may not be observed here but at least people have heard of them thanks to their favorite series. Elements of American “culture” show up all of the time and more than once I’ve found myself saying, “have you seen the episode when…” to explain something I’m talking about. Be it boy scouts, science fairs, or the bookmobile.
Friends and the Simpsons are by far the most commonly-used “dictionaries.” Seinfeld, however, never managed to fully push into the Spanish market. Although it’s a mystery to me, the show simply didn’t gain the success here that some of the other series did. Although I find myself wanting to refer to it in normal conversation, I limit myself to the shows which I know were widely viewed here.
Perhaps TV is a universal language as long as you stick to the script.